Check out their rating on the garden watchdog...it's not pretty!
As for other sources, try posting on the perennial forum.
Lots more traffic over there.

Ordering by mail is always an "iffy" experience. We find that buying locally is much better, but sometimes you need something the local nurseries just don't have. We have had good experiences with Pinetree Seeds www.superseeds.com and with Value seeds. When we lived in NY we bought from Spring Hill a couple of times and weren't unhappy with the service and product. However, by time you pay for the shipping, get the small plants in 21/2", 4", or even 1 gal. pots and hope that they arrive during your planting season, not the shipper's digging season, and baby them along--we prefer to save the money and drive to a nursery within 100 miles that has what we want. Besides, they may have something you really, really need and didn't know it! That is why we go to Antique Rose Emporium and to Chamblee's Roses, although both offer mail order plants. Try the "Rate Vendors" site on GW's garden forums. There is a wealth of information there!