[jxboot]

I would fold. Mainly because I highly doubt this guy would risk ALL of his chips without having a good hand. You said yourself..

[ QUOTE ]
he certainly knows what he's doing

[/ QUOTE ]

I'm not saying that all-in in that situation is a good idea but knowing that he's pretty good (from what you say) I highly doubt he would risk all of his chips in that situation without having a solid hand.

If he has TT, his thought process could be (given the fact you guys have played a lot of hands together) that he knows you're pretty aggro and this could be a chance for you to hang yourself. From his point of view...

You raised preflop (not sure on your stats but for argument sake we'll say he thinks you're TAG) putting you on two high cards and JJ+ (assuming he has TT, he wont put you on TT+). The flop was amazing for him so he checks raises because he knows you're gonna c-bet a) because he knows you to be aggro and b) because a c-bet makes sense here. Once you make the call he can assume you have a high pair, JJ+. Because you called the flop he could think that you're going to commit yourself to the hand and he thinks that you're going to pay him off here.

Thats the only logical thought process I can think of if he has the hand, I'm not saying what he did was right but for a person who might "know what he's doing" this thought process makes some sense...I think...or I could be giving him way more credit than he deserves ...