raise or fold?

[siegfriedandroy]

hand 1: i am in the big w/ k4h. one unknown late limper, and sb completes. flop is q 10 8 w/ one heart. checked around. turn is a rag heart, and sb bets. i am getting 2.5 to 1. no stats on sb yet (new comp), but i remember him as generally taggish but capable of getting out of line (and perhaps stealing in a spot like this- not that that is necessarily out of line).

2nd hand: heads up, 1st hand. i raise a2o, he calls, and i flop a gshot ( 3 5 10 rainbow). he donks. i suspect his donk likely means a pair, but ive definitely seen him make some plays before. my action?