Please comment on this hand

[Buccaneer]

I have no real feel of any of these players. Looking for comments on hero's play please. As always do not hold back, feel free to express yourselves.

Party Poker Limit Hold'em Tourney, Big Blind t50 (5 handed) converter (http://www.selachian.com/tools/bisonconverter/hhconverter.cgi)

Button (t3688)
SB (t732)
BB (t1850)
Hero (t750)
MP (t980)

Preflop: Hero is UTG with 7/images/graemlins/diamond.gif, 7/images/graemlins/club.gif.
<font color="#CC3333">Hero raises</font>, <font color="#666666">1 fold</font>, <font color="#CC3333">Button 3-bets</font>, <font color="#666666">2 folds</font>, Hero calls.

Flop: (7.50 SB, t375) 4/images/graemlins/club.gif, 5/images/graemlins/diamond.gif, 5/images/graemlins/club.gif <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets</font>, Button calls.

Turn: (4.75 BB, t475) 5/images/graemlins/spade.gif <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets</font>, Button calls.

River: (6.75 BB, t675) T/images/graemlins/spade.gif <font color="#0000FF">(2 players)</font>
Hero checks, <font color="#CC3333">Button bets</font>, <font color="#CC3333">Hero raises</font>, <font color="#CC3333">Button 3-bets</font>, Hero calls.

Final Pot: 12.75 BB (t1275)

[Easy E]

If the button 3-bet preflop, why are you check-raising the river?

I'm guessing you were beaten since s/he rereaised again on the river.