For me, I'd have to say Red was my favorite of the R/G/B/Y series. The color blue never held much appeal to me, Green was Japan-only, and Yellow I loathed with a passion. I outright hated that game, mostly because I got it when I was Seven Years-Old, and didn't know I could get a Mankey, so I spent hours leveling Pikachu and Pidgey enough just to beat Brock. I also hated Pikachu, surprisingly enough. I was sick of it, being everywhere in the game, on the television... It just got annoying quickly.
Yes Yellow was HORRIBLE because of that i levelled Pikachu to level 15 jsut to beat brock! that took FOREVER i absolutely DESPISED doing that not only that but since i was so youngf and didn't want to leave pikachu, well pikachu is PATHETIC to be blunt even at lvl 100 if loreleis dewgond attacks with ice beam it'll take half your hp!!! Pikachu is absolutely useless. Even if you had to train so much for brock even at the second gym Pikachus stregnth mind you! it was still difficult! one attack would take out half your hp! and the last gym? Pikachu was an absolute peice of junk. I suppose it's a gltich but if you use an un-evolved un-trained Bulbasaur againts Nidoking or Nidowqueen they will only use defensive moves, so i just slowly beat them down with bulbasaur. Thats pathetic a lvl 10 bulbasaur doing better than a level 51 pikachu. Nintendo don't ever do that to us again! gives such a pathetic starter... (^^ sorry for the rant that jsut rlly brought back horrible memories)