A4s flop decision

[Redeye]

Here is what I thought was a somewhat interesting flop decision. No strong reads here, but we can assume no one is out of hand, so no really laggy players.

Should I raise or call here on the flop? I have a nice gutshot draw, combined with a backdoor flush draw and my 4 (card) outs are probably good. Normally I would raise here, but MP2 raised PF so he probably either had a large PP like KK-TT which I don't want to fold here, or a larger ace, in which I'm getting 3-bet. What action would you take here?

Thanks




Party Poker 2/4 Hold'em (10 handed)

Preflop: Hero is UTG+2 with A[img]/images/graemlins/heart.gif[/img], 4[img]/images/graemlins/heart.gif[/img].
<font color="666666">2 folds</font>, Hero calls, <font color="666666">1 fold</font>, <font color="CC3333">MP2 raises</font>, <font color="666666">3 folds</font>, SB calls, BB calls, Hero calls.

Flop: (8 SB) 3[img]/images/graemlins/heart.gif[/img], 5[img]/images/graemlins/diamond.gif[/img], A[img]/images/graemlins/diamond.gif[/img] <font color="blue">(4 players)</font>
<font color="CC3333">SB bets</font>, BB folds, <font color="CC3333">Hero </font> ???



EDIT: Clicked post before I had actually gotten the post set the way I wanted