Here is a position that I struggle with.  I know there are three different ways to handle this but with this configuration I seem to always lose the momentum and usually end up with a poor pawn structure further on down in the match.

I almost never chose to retreat the bishop to h4, even though that would make the King side pawns weaker if g5 to continue the attack on the bishop.

I'm wondering if the better move would be bf4.  Any thoughts on this would be appreciated.

You have to consider why you're moving your bishop to g5 in the first place.  From the configuration you've posted, it looks like you pinned the N between your B and the opposing Q, and then at least two moves passed where he moved his B to interpose, and then advanced his h-pawn.  The problem is, whether you retreat or trade pieces, N for B, you have allowed him to develop more than you, he's ready to castle, and you've wasted several moves.  I usually don't play such pins unless I have a way of countering my opponents moves to block the pin, or I really do wish to trade pieces.  Alternatively, you can use pins like that to give your opponent a bad position.  For example, if you manage to pin the N after their same-colour B is gone from the board or cannot interpose, then if you trade N for B, you force them to either bring out their Q early, or double their pawns.

Bottom line: have a plan, don't just play "good" moves simply because they are available.

Yes, I agree Onosson with the trading of B for N. This is why I almost always make the trade when in this position. But you did say something very interesting to me that I had not really given much thought to (I'm weird like this), and that is to wait for further development of the blacks bishop to prevent interposing.

As for wasting moves, this is why I don't like to play a Queens pawn game, I just need to study it more.  But what about bf4 at this point, I have never played that and wonder if that is a way to keep from losing momentum.

Something I have noticed is that a lot of players will continue attacking the bishop and weaken their king side.  Depending on the opponent, I will retreat my bishop if I believe they will continue the attack. 

Here are some ideas:

1. By playing ...h6 Black made a weakness on his kingside.  If he castles there you may want to consider a plan with O-O-O and g4.

2. You (White) have more space and you want to avoid exchanges.

3. If Bh4 you have to look at simplifying lines starting with ...Ne4 - see the Lasker Defence to the QGD.

4. If possible, prevent Black from playing ...e5 which frees his bishop, unless you can give him another problem (like an isolated d pawn) in return,

5. All this makes it look like Bf4 is worth a try!