Chess: An Interesting Exchange Sacrifice

In another game I played last night, I had a rather interesting decision about whether to offer the exchange to my opponent or not, turns out the computer hate my decision, but I still like the decision.
Perhaps I have a weakness with letting my opponent take my Rook with a fianchettoed bishop, but he just leaves so many weak squares around his king when he does so.

I don't actually like his move e5-e4 I think it leaves the knight to be stranded on h5, but that is for another time, I have a decision. Move the rook or take the pawn, I decided to take the central pawn and sac the exchange, but I think I have decent compensation.
A few moves later I had him beat, with a nice little exchange that left his king vulnerable.

I just played Nef4, I guess he felt forced to take this knight, he could have played Ng7 to try and survive, since this leaves him in rather bad shape, I played a little intermezzo here Nf6+, after which I will take the knight and play Nh5+ and his king is pretty vulnerable on the long diagonal.