Taking with pawn vs taking with piece

Sometimes there's a choice of recapture- with a pawn or a knight. Taking with the pawn gives you an isolated pawn but a more active position, hwereas taking with the knight gives you a better strucutre but less activity. Which would you recommend in this position?

What about Qb3 and if Qe7 taking with the pawn with the nasty threat of Re1?

OK haha I guess thats a move in this situation but let's say you had to retake...which one would you retake with?

I thought so: a d4 opening. I've had the same question for the last few months. After one bad game against the computer where I captured with the knight and quickly lost a tempo from having my knight driven off (which would happen here after Nxd4 ...c5), I've started capturing with my pawns instead, and I've had much better luck. This type of position seems to arise very commonly in d4 openings. I still don't know a good answer--I've never seen the answer in a book--only that in my experience capturing with a pawn prevents an annoying tempo loss and seems to give me a better game.

Besides, I think I would have played 6. dxe5. But following your point, I'd probably take with the pawn. It becomes isolated, but this is typical of the QGA anyway, and white is ahead in development and has open lines against black's position. I'd probably even consider the B sacrifice in f7.

I will play Nxe4 because I do not want a isolated pawn.

Why?

Very position dependant I think but I'd play exd4 in that position every time it came up- improves the bishop, opens a file against the black king which will give your rook a good purpose, and the d4 pawn is currently a stronghold in the center. Good position to take an isolated pawn to me.

I'd take either the pawn therefore setting up a long open file for rook or queen

Taking with Q is the worst it gives black a free tempo and development via 7...bc5! Taking with the pawn is decent if you understand IQP structures and strategy well. There's also other moves you can do here like 7...Qb3 creating a threat on f7 and you can follow up with re1 or exd depending on how they address the threat...

I think the general consensus is that taking with the pawn is better, but I guess it really depends on the position. Thanks everyone and have a great New Year!