A lot of girls would choose the bad one since most young girls (assuming that you are young) like that rush. They would rather choose fun over most things and things would either end badly or just end with distaste.
That's why, I personally would choose the "boring" guy. I mean you may think that he's not that great and that he's really dull, but you never know. They may only seem that way on the surface, but are actually quite wonderful. I know several people like that. They appear to be really uninteresting at first, but after talking to them and getting to know them, you realize that they are pretty cool and decent people. Also, you said that he's really cute while the other one is only kinda cute. So that's a plus, right?
The bad guy is of course more appealing. He's all showy and flashy and he's cool. He'll probably give you a good and fun time. He's more likely to help you step out of your comfort zone and do some pretty awesome and adventurous stuff. But eventually, you'll most likely see a guy who isn't someone you'd like to be with. They can either have a messed up family life, they like to do illegal or unacceptable behavior, and/or they are players who cheat regularly. Is that really someone you'd like to be with?
So that's why I'd take my chances on the good guy. If he does end up being dull, then you can simply end it with minimal damage done. You can go on with life as you did before. But with the bad guy, there's a chance that you may never be able to go back to the way things were after you two are done. Are you really willing to risk that just for a rush? Thrills only last for a short moment. But the damage that the bad guy can potentially cause will be with you longer than that rush. So choose wisely. I wish you luck.