I have had mixed experiences with J&P. The plants are large and in good shape when received... but I have had several roses NOT come out of dormancy - i.e. they died. On the otherhand, some have done very well. Considering the prices of this company - I would expect a better survival rate than what I have experienced. I have had better luck with Wayside Gardens. The only negative I can say about Wayside... is that they often backorder something... and after a long period.... finally admit that they are not going to fill your order as placed. By then it is usually getting rather late in the season and if you were counting on those plants... you are out of luck.
The company I have been MOST pleased with for mail order plants - is High Country Gardens. They do not do roses - but for the other items they carry - I have found the plants to be EXTREMELY strong and hardy. I think their prices are reasonable too.