GG1 was charming in its own way; it had super swole combos, tons of infinites, and combo-ing into an instant kill was always hilarious. I always thought of it as a proof of concept and GGX as like, the first prototype. I liked #Reload best overall though that's probably more to do with who I was and how I played games at the time rather than #R being legitimately the best game in the series.
/ felt like Guilty Gear on ice to me, it was slow and dull and most things I'd enjoyed with the earlier versions had been removed. It's like Arc Systems Works looked at how a good portion of the XX and #R characters had such crazy combos and decided to tone most things down making the game slow and boring in the process. I was never quite sure if I liked Accent Core or not. It felt the exact opposite of / to me; instead of giving everyone homogenous and mild gameplay they gave everyone ridiculous crazy shit and then every combo ended up with ground bouncing, relaunching, wall bouncing, ground sliding nonsense combos that took too long to end so again I got bored.
The extent of my AC+R play has been beating up the local guys that fancy themselves Guilty Gear players. There's not much of a scene for the game in Dallas these days. Maybe it's great, I'll probably never know. I'm Super looking forward to Xrd though.