I actually made a big-ass Excel table before buying my PS4 comparing Pro vs OG versions, because I paid 330€ for my slim (albeit with 2 controllers and Uncharted 4), and a Pro was 350€ (although it probably would not have been hackable). So I made a list of all the games I would play and seeing as how I am still using a 1080p display, I found almost zero reasons to go Pro. Maybe The Last Guardian I guess, and multisampling, but I've been gaming for more than 20 years without multisampling so what's a few more years

?
Btw, I don't know how significant changes between 4.55 and 5.xx are - do you think there could be some problems with save games? I mean, I still haven't upgraded from 4.05 to 4.55 so I have no idea if I'll get to keep my backup saves or no, but I guess those two fw-s were more similar to each other than 5.55 and 5.xx?