let's start from the G ver. stock 2.3.5 rooted rom firz

Pro's- very good battery life,buttery smooth UI once u updated to the DZKI1 f.w, battery temp won't rise fast, seems like a new proximity sensor cos when u switch off the light in a dark room u'll notice some glowing in red at the proximity sensor hole, last but not least THE BEST OF ALL WAS it is made in korea by samsung even the battery is made in japan finished in china and seems to do great in terms of gaming an in ANTUTU bench i tested both ver in 3d graohics and the G spec scored 1274 with it's capped max freq at 1.008ghz compare to the NON G ver. which just managed to get 1178 with a stock doedex KI3 rooted lite rom and running at 1.2 ghz, next in terms of testing 2d graphiocs the G spec scored 303 and the other one scored 296 only which i think samsung had done some tweaks to the POWER VRsgx540 GPU and testing the CPU the G spec gets 2970 vs 3294 obtained by it's brother thx to the exynos chipset

BUT....... the worst part was although samsung quoted it as running a dual core 1.2 so does other third party software in market but i noticed samsung capped it to just 1.008ghz only[COLOR=red](maybe to make batteries last longer) and fonts inPAPAGO looks very very smalland available freee ram in G spec was all the while 600++ compared to 490-500++ so if i had to choose either one only it would be the non G ver cos imo it's less laggy while browsing the net and very fast in opening apps/multi tasking which what i need basically although in terms of gaming it's not too bad at all but tends to get overheated faster so imo wether it's a "G" or not there should not be any problem at all,
Just based on my personal experience to share it with u guys but for custom rom or overclocking i feel sorry for the G spec but also without all these the phone does incredibly well too