IIRC - It’s lighter weight and it has a better / lighter hub (DT Swiss 240’s for the RSL vs 350 for the pro).
Is it worth it? If you have the money and/or if the weight savings are going to make that much of a difference to you. The good thing is they both have lifetime guarantees.
FWIW - When I upgraded to the Pro 37 and I lucked out finding a set at a Trek corporate store, they didn’t even have them available online. I hope new stock has come in.
I have to say I’m pretty happy with the Pro 37’s on my Domane. Nice upgrade to the stock wheels that came with the SL5. Converted the stock wheels to a tubeless gravel set-up.
