i usually do BB rows just by grabbing the bar but ive been ppl do BB rows with a reverse grip...which seems like i could hold heavier weight a lot easier but does this effect how the lift hits the muscles or not?

IMHO its overhand or not at all. I like my back close to parallel though too.
Jason
I agree overhand all the way. Underhand brings in too much bicep.
I like doing underhand rows because I can pull more weight and I just prefer it.
Overhand... I dont get the same upper back contraction at all with underhand. But then again Dorian Yates refused to do anything but underhand and look at his back... all a matter of preference and everybody's own individual body mechanics.
so if it feels more comfortable and feels like i could lift more weight then should i try and use underhand?
yes do whatever you feel most comfortable with while maintaining proper form and using your back to pull the weight
If you go overhand use a thumbless grip. It seems to hit the lats even harder. If you use heavy weight you will probably need straps.
i currently use overhand but it seems my grip tires out before my back
I prefer underhand, it allows me to do alot more weight. You must focus the movemnt on you back however. No cheating
It really depends on your own body mechanics. Most likely one or the other will feel better.
I prefer underhand - it gives me a much better connection and feel. It is true that the bi's are used more, but if you are connected to your back, then it is minimal.
I struggle to get in a groove overhand and I end up placing a lot of stress on my bi's and lower back as I bounce around.
I do both. When I do underhand I make sure to really feel and concentrate on my back. I normally dont even feel it in my bicep just back. I can lift the same for both. If u feel too much bicep then its probably to heavy.
I prefer to vary my grip distance and vary my use of a supinated (hands up) or a pronated (hands down) grip. Even a dumbbell row variation will provide a semi-supinated / neutral grip.
I go double overhand, throw in the hook grip when it gets heavier and then throw straps on once my grip really gives out.