Hello All-
 
I am looking to beef up my virtual instruments - especially horns. I mostly write pop/rock, and so think that a virtual instrument with horns tailored toward Jazz and Big Band would be the way to go. Right now, I am tending toward the Garritan JABB3 software, which seems fairly well regarded and reasonably priced, but would like any suggestions this forum has to offer. Cost is an issue for me, but I would like to hear about very good products also - even if over my limit, which is right around $200 US. 

I was impressed with Jazz Horns from Straight Ahead Samples, who I'd not heard of before accidentally stumbling onto their NAMM booth last January.  Very realistic-sounding, e.g. when they do a trumpet section it's actually a trumpet section with multiple players and instruments. Includes bass trombone, which is gobs o' fun. Tenor, alto and baritone saxophones. 
 
This is for serious composers, though; you might want something simpler. At $300 it also exceeds your stated budget. But sound-wise, it's top-tier.
 

I use MOJO horns from Vir2 most of the time but still think one of the best horn libraries ever is First Call Horns, which is a relatively old package. Not sure what it goes for now but you could google it. You might also listen to Session Horns Pro from NI. Can't vouch for that as yet as I just received it with my K10 ultimate upgrade but haven't used it yet. Good hunting.

EDIT: Big Fish Audio still sells FCH @ $199. Maybe find it for less elsewhere. Absolutely killer diller.

Vintage Horns from Big Fish also tres fab.

I purchased NI Session Horns second hand on KVR forum fairly cheap. It covers a lot ground sonically, but not the ultimate Jazz/POP Brass library. I tested all brass sounds available to me and figured they all are usable, depending on context/goal. Here is the test:
https://soundcloud.com/s0undwise/brass-test

Thank for the suggestions and soundcloud comparison.
 
I think I may start a related thread specifically about the Garritan JABB3