Kabuto is ok on the heals, but when it comes to clones, he's not the greatest.
Sai on the other hand, he got some really tanky & strong clones.
4th war Sai best ofc, but hard to get atm, but the 1 for pvp coins, is good enough.
he don't need any chakra :P

Yeah, their there to protect your team usually from auto attack, but ppl like Sai,Kankuro & Sasori,
got both strong protection & good damage. :P

What you really don't wanna meet, is Sai with 4+ clones + Crimson fist with Inner Gates, pretty much the bulldozer of attacks is coming :lol