There is also b x b5; q x b5+, qd7; and if q x q your king is left way better than while fir the endgame. Interesting position
Queen-trade situation
@1
"I think Black should do this because he is then guaranteed to have a chance to capture one of the two bishops."
Yes, 1...Rb8, but then 2 Bxd7+ Nxd7 3 Bxd8 Rxb7 4 Bg5 Rxb2 is better for black.
"Black can play Rxb5, attacking the queen while his bishop is defending the b5 square to capture the queen if White decides to take the rook with his queen." ++ Yes, indeed: 2 Qd5? loses.
Consider the situation below with Black to move:
There are several possible queen-trades to consider here, but I'm looking at two of them right now. If Black plays Rb8 to attack White's queen, the first possible queen-trade come from White capturing the knight on f6 to attack Black's queen. If Black then captures White's queen on b7, White will capture Black's queen on d8. Should Black do this? I think Black should do this because he is then guaranteed to have a chance to capture one of the two bishops.
The second possible queen-trade comes from White playing Qd5. If White plays Qd5, should Black play Nxd5 even though White would then capture Black's queen on d1 with his bishop while simultaneously attacking Black's knight on d5 with his pawn on e4? I don't think so because Black can play Rxb5, attacking the queen while his bishop is defending the b5 square to capture the queen if White decides to take the rook with his queen.