At the moment we're saltwater/reef only. We recently expanded and are putting in freshwater... to pay the bills.
I started with the suppliers that my former employer used... figured that was "as good as it gets" but through this forum I met Mary and Steve, and another great supplier who found me probably through my FAMA ad or something. I get courted every week by livestock suppliers but I'm happy where I am. My biggest complaint is variety, but I also understand that there are sometimes trade-offs. I can usually get what I want/need sooner or later, so it's a matter of educating the customer and being patient sometimes.
I carry substantial amount of tanks and tank furniture. I can get the high-end stuff in, but as Glenn said, it's a PITA, so it's usually onesies and twosies as special orders for those who want them. I don't push crap... but the middle of the road, easily obtained stuff seems to sell best.
I'm adding the freshwater to expand my customer base and attract more people to the hobby. Many are so intimidated by saltwater... get them interested with some guppies or tetras, next it's Africans or Discus... then a reef
There's always room for one more tank....
I too am looking for info on freshwater wholesalers in the Southeast. For everyone that has recommended a given wholesaler, I find somebody else who says, "EWWWW" about them...
I can see it being a bit subjective, but by and large a place either deals in quality or it doesn't....
Jenn