I’ve been using the MP1 for a number of weeks now in conjunction with a Tacx Neo. It’s really been transformative in terms of making for a more comfortable realistic feel during indoor trainer rides. Seated, the motion is very subtle at higher cadences but becomes more pronounced as you start to drop your cadence down and start to grind out some efforts. As others mentioned the fore and aft motion is more notable than the side to side.
I’m definitely more of a long distance endurance type rider than a sprinter, but I’ve been doing a lot of 5s, 15s, and 30s burst efforts since getting the MP1. Out of the saddle, as mentioned above, the bike doesn’t have the same direction side to side motion that it would have underneath you outdoors. However what is interesting is how “stable” the entire platform feels; it moves but the trainer itself it tightly fixed to it and everything feels controlled. It is hard to describe, but if you aren’t using an MP1 (or other rocker), you wouldn’t want your trainer moving when you stand up and sprint. If fact I’ve seen pictures of people who actually weigh down their trainer legs with weights/kettlebells to keep their trainers from moving. However on the MP1, the platform allows some movement but ultimately it feels like more power is going into the pedals. The result has been that I seem to be putting out higher power numbers as compared to prior to the MP1. It could be coincidence based on where I am in my training program, but I think there is something to it.
Everything else feels great on the MP1. After a while you just forget it is there, but then you finish your workout and realize you aren’t as sore. Today I did a two hour upper end Zone 2 ride with 5 second sprints every two minutes for the first hour and I felt great throughout. In the past, by the end of two hours my backside would be feeling it with a longish two hour Zone 2 effort, but no issues at all today.