Saw the earlier discussion about Bluestone, and wanted to drop my 2 cents. I have purchased all my perennials except bulbs (which I bought from Breck's before I knew better, but have had good results with, generally) and Alstromeria (which they don't carry, unsurprisingly given their climate) from them, based on recommendations from many, many neighbors and friends who buy from them. That's 39 plants.
Of those, 3 didn't make it, none of which were really their fault. The first one to die was because of a shipping delay last spring, where my shipment took 7 days to reach me (should be 2-3, has been 2-3 since). I actually think it's a testament to their quality that the other 9 plants in that shipment survived that kind of delay. I could tell it wasn't going to make it right out of the box, but planted it anyway on a wish and a prayer. It took about a week to fully die. They replaced it without question. Then, out of last fall's shipment (15 plants) 2 didn't make it, because less than a week after I planted, we got 5" of rain *in a day.* That flooded the yard and the plants (and my basement, and my neighbors' basements, and half the city...at least I'm on high enough ground that we didn't get the sewage backup like a lot of places). I feel like I'm lucky I only lost 2! They also replaced those without question. All 3 replacements are thriving, as are the 14 new plants I installed this spring (about a month ago now...they're all larger/sending up new growth), including Hellebore.
I haven't had problems with the coconut pots breaking down. Well, as far as I can tell. Even where the plants died, the pots broke down within a season (replanting was always in the next season...so spring plant that died replaced in fall, fall in spring), so that I was only pulling a few intact scraps out (not the whole pot, but maybe 2-3" strips). I haven't dug out the plants that made it, of course (they're all barely a year to brand new), but given their robust growth (you can find pictures of my 7-12 month planted Stoke's Aster and 12-month planted Siberian Iris around the site), I have to assume the pots aren't hurting them.
Just my experience. They're north of me, so that's one thing I was looking for in a nursery. They definitely stand behind their guarantee. And, as noted, neighbors and friends with nice yards rave about them.