What i enjoyed about Kick-Ass was not the cursing or the violence, in my opinion a good comic and movie can do without them, but i liked how real it was. An average joe longing to be a superhero, i believe that speaks for a lot of people. Speaks for me at least. And how being a superhero had its consequences like you could seriously, seriously get hurt. It makes the whole concept of superheroes believable.
Team 2. Aside from the fact that Joker's side would probably have weapons equal or better in fire power over shotguns and hand guns, the battle takes place in Arkham Asylum and who else knows Arkham Asylum better than the Penguin? Harley does, now who else knows Arkham Asylum better than Harley? The Joker does.
Hit Girl and Big Daddy have body armor as part of standard gear; Joker's side do not (tell me one instance of these Gotham villains wearing bulletproof vests). So even with guns... the Kick Ass team has at least this advantage.
Harley dodges bullets? Well she's the only one who can do this then. Hit Girl has been shown to be able to dodge bullets in the movie version and since Big Daddy trained HG he can probably do it too.
In firefights, I think Big Daddy and HG have the edge. Because they are known for their skill with guns (Big Daddy with snipers and shotguns, HG with handguns) whereas I don't think anyone in the Joker team is really outstanding in terms of marksmanship (Joker's always relied more on traps and Penguin was never really much good at shooting; Harley a marksman on par with Hit Girl? Give me a break).
Last time I checked, Joker was not a very good hand to hand combatant (moderate at best) and has never TRAINED. Hit Girl, Big Daddy, and Kick Ass all train on a regular basis...
If the gap is closed the team of TRAINED heroes will rip the villains apart (especially if Hit Girl has knives and her blade stick as part of standard gear, her height difference will also throw all the villains off).
So in most scenarios with standard gear... Kick Ass team for the win.