This...stay out of the middle tree except for those critical hit boosts and some health orbs during phase lock...then get the duration and cooldown buffed up and put everything else on Cataclysm and destroy everything.
I used to be a Street Fighter like you...then I took a Spiral Arrow to the knee.
I have soloed with all, all the way through UVHM and DLCs. And they are ALL just fine to play solo. It truly depends in what kind of character you want to play. And even then, there is quite a bit of build diversification within each character. Sal - Wanna be a tank? Or do you just wanna shoot two guns simultaneously forever? Maya - Healer? Yup. But with a little Ruin she's goddamn devastating. Never use slag again. I feel she's also a good choice if you wanna use guns of all elements liberally. Axton - His turret is both a distraction and potential bomb/perpetual slag dispenser. He's a pretty rounded character and is especially good if you disdain elemental powers and go straight power, i.e. Jacobs. Zero - Definite learning curve compared to other characters. Yet whether you wanna be a melee monster or two-fanged blaster, he is nasty. Gaige - Shock anyone? Anarchy builds let you just kinda "point n' shoot" like a cheap camera. And don't let anyone poop on the "girlfriend" tree. Deathtrap is awesome. Especially if you use him as a partner and not a crutch. But he works pretty well as a crutch if you're so inclined. Kreig - Very diverse builds here. Go melee and release the beast all over your enemies' faces. Or set yourself on fire and shoot a shotgun. Oh and bloodsplosion chaining is a blast. All in all, they are all fun. You can't miss. Hope this helps at least one iota.
I have all characters maxed out. Honestly it really depends on your play style and skill. Axton is considered the easiest to play with only because his turret can become very powerful. Sal has insane damage output. Maya is a healer but honestly i have never used her as a nurse. Ive used her to melt faces with her elemental buffs. Gaige can also stack her damage so high that most enemies will not survive one hit. Krieg is so much fun to play and with his bloodslplosion skill he can totally destroy a mob in one hit. Zero is hands down the most powerful character, but also had the steepest learning curve and really isn't as impressive until you are in the high levels. But once Zero gets there, watch out. Zero cash one hit bosses and kill them.
Well just depends on what you mean by best, I have a lvl 61 zerker, assassian, and siren, and a lvl 50 merchromancer. I have also fooled around with my friends lvl 61 Kreig. First off all characters can be monsters and destroy enemies with the right build and equipment. I had the most fun playing as Maya, Krieg is also a blast to use, on the other side of it your gonna get the most damage out of Sal period, I have soloed every raid boss with him with realitve ease, if the game based difficulty on characters he would be easy mode. But again you would have fun with any of them, I would have to agree that Zero would be the most difficult to learn.