Another thing to consider is batteries.
I’ve got a LSO Stages (latest Gen) and it eats batteries like a demon. I get ~40 hours out of a battery. Basically 1/month.
Not only that, but when the battery gets low-ish, the PM starts giving out very bad data. There were rides where I had to stop multiple times & zero just to get good readings.
Bottom line — lots of batteries.
That’s weird, my Stages is a little older(gen2) and I get close to 200 hours out of a single battery. I have the same issue with bad data when it gets really low though.
What brand of battery do you use?
Some generic brand. Picked up a cheap fistful at Ikea.
Recommended brand? 
I use these: Amazon.ca
Work well for me 
The most common tool I have seen used is the DCR one.
Personally, I just run my dual power meters for a ride or two, at varied power levels, displayed on dual devices, and then watch the power live. I take that as a quick analysis and make the general adjustments based on a simple comparison.
You can sure dig in deep, but I find I have less interest in that and it only distracts from the work I want to do. I can overindulge in many things, and have done so in training in the past. So attempt to strike a balance with how much I dig into the data. These days, I take a stance that is more towards the minimal side, but one that includes power data.
I have a Stages Gen3 and it’s been pretty good on batteries. It’s on its 3rd from being a year old now. I did get some 3000+ power results when the battery was low; like 6%. Funny thing is the Stages iPhone App said the battery was good/green/full but the TR App starts flagging it yellow at 18% battery left. At first I called BS on TR for reporting the battery low but on my last outdoor ride it died. I now believe the TR app for battery life on my Stages and not the official Stages App. Also if you travel with your bike where is gets shaken around from the road vibrations I can see that waking the sensor up and making the battery not last as long. Either way I love my Stages PM and plan to get another this year for my mountain bike.
This happens to everyone. It’s a Bluetooth issue. A brand new battery can read 18%.
Most people are not 50/50 balance and the difference changes with wattage. I am about 47/53 when going hard but more like 43/57 when going easy. I don’t know why it changes but it does and my son has seen the same sort of thing. I recently got Assioma Duo on my road bike (my 5 year old Pioneer died) and a Power2Max spider meter for my MTB. Both are about $650 and have worked perfectly. I like the Assiomas because when I travel for work I take them with me and replace the pedals in the hotel fitness room bike. That way I can do a good workout, where I actually know what the intervals, are on the road.
Just my experience: like many. started my powermeter career with Stages. Went through three dying units, 2 of them never saw day light because they were used indoors only. So no water issue or so.
This was one part, the other part had to do with my legs. Soon I expected that later into rides something was wrong. However, I only figured it out when I got pedal-powermeters which measure a true L/R balance (no pseudo-balance as with spider based PMs): my legs fatigue differently. L/R got completely out of whack when tired. Threshold intervals, the last or last two, completely off. Long endurance/tempo/sst sessions: all good in the beginning, off later.
I race mainly >4h events, hence, what’s happening later in a ride is important to me.
These days the price difference between a real PM and a left-only is not that huge anymore, I would think twice. Left-only PMs are not cheap either.
Stages L is cheap only because the 105 crank (5800 iteration) is on sale ($318 instead of usual $530). Otherwise it’s almost same as a Power2Max NGEco.
The only minor issue with the NGEco is that the spider is from Rotor and not a stock Shimano, but that’s purely aesthetic and doesn’t detract from training or riding in any way.
Edit: Only issue I see with Power2Max is that it isn’t so straightforward for someone less knowledgeable like me to figure out what configuration I should buy for Shimano
What configuration? I ride two P2M Rotor 3D24, one with Di2 Ultegra and one with mechanical Ultegra. Works flawlessly.
After reading DCRainMaker and mailing Power2Max, it’s now clear that I would need Rotor3D24 and Rotor cranks, but it’s not at all obvious from the Power2Max website that I’d need to do this for Shimano 105.
Double the strain gauges, double the chance of one not being quite right.
Like Shaneo said in his vid, it could just have been his particular unit. Would be interesting if he sent it in for warranty and they gave him a different unit to try??
As for the spiking when manhandling the cranks in a standing sprint/climb, I think some of the fluctuations he has seen in both the Stages and the Zwatt cranks against his Assioma pedals is down just as much to the mechanics of the situation (crank vs pedal spindle).
Not many of us have the blessing (or curse) of riding bikes with multiple power meters like Shaneo and Ray at the same time to go about comparing 1W and 2W or 5W differences here and there. And this can actually detract from the information provided. Yes it gives us a good benchmark against a Neo or Assioma, and can aid in our buying choices (stayed away from the Gen 2 stages myself due to the drop out issues that Shazza spoke of, but happily went Gen 3 since I’d be able to go bike jousting with it, thanks to Shaneos review with his farcical broom handle, which must be pointed out, does not win one a jousting battle…need something a little stronger, and more carbon :P). If all you’re running is a left sided 4iiii or Stages, then that is OK too - consistency in data is key, just like keeping to a training schedule.
I prefer to use my indoor sessions as my “benchmark” intervals, and when on the road, the PM is mainly for pacing and ensuring I don’t go too hard when I’m supposed to be cruising. I don’t have one on my MTB('s) (my main sport), so learning the RPE is a better thing to evolve rather than worry too much about 5W here, or some w/kg figure there, that at the end of the day is entirely only ever relevant to me. I couldn’t care less if someone told me they were 5w/kg (apart from an encouraging, good on ya mate, to them).
You’ll need a broom which is horizontally stiff and vertically compliant to win a jousting event 
Buy something nice, you spend so much time on the bike. Second hand screaming deals can be found
I have a two year old Stages gen2 and in Nov paid $750 direct for a new Ultegra 8000 crank with LR power. Both have worked well, no issues with batteries or accuracy when compared to my Kickr. Spent a week looking at the extra data from LR, and rarely look now. I will quickly look at L/R balance in Garmin and its usually 51/49 or 52/48. Have never found dual-side 4iiii ride-ready in stock when looking, except for $1500 Dura-Ace and so 4iiii is $750 and I have to send my crank to 4iiii for installation. That is more expensive than when I bought new crank from Stages.
After buying the Stages gen3 @stevemz posts got me to finally decipher Power2Max website and realize that NGEco with my current Shimano chainrings is roughly $675 shipped. Had I known that in Nov, would have gone for NGEco and saved $75. Otherwise Stages LR gen3 is working well and I’m happy.
You and Ray have some serious clout in the industry, Shane, especially to illicit that fast of a response.
You must be somewhat proud of yourself having built up your channel to what it is today…heck I even watch all your vids even though 90% I’ll never buy! Your tubeless videos have been comedy gold, I must say!
Keep up the fantastic work! And I look forward to “Stages Left / Right made…right???” video soon 
I’ll keep your experience in mind the next time I’m shopping for a power meter.
Flat here but a lot of wind, so the power meter really helped with training outside.
Went from Left only Stages to Left/Right Stages, and found that the power distribution between my left and right legs are always within 1% of each other. So for power measurement I think taking Left only and doubling it is fine (which is what a Left only powermeter does, basically iirc).
There are some other metrics like pedal smoothness and effectiveness that are available with LR powermeters, but if those are not important, then really you probably aren’t losing much going L only.