Tough flush flop decision

[Cucumber]

$100 NL FR (right forum?), Hero (been playing about 35/25/10 for the last hour but just switched gear to TAG a few hands ago) is at the button with A[img]/images/graemlins/club.gif[/img]A[img]/images/graemlins/heart.gif[/img] with $80.

UTG folds, Villain (32/8/3 after 40 hands) UTG+1 with $34 openlimps, fold to the button, Hero at the button raises to $4.50. Blinds fold, villain cold calls OOP.

Flop: 9[img]/images/graemlins/spade.gif[/img]7[img]/images/graemlins/spade.gif[/img]3[img]/images/graemlins/spade.gif[/img]


Villain checks, Hero bets $10.50, Villain raises to $29.50 and is all-in. Hero... ?

Looks like a marginal decision really. What do you guys think?