Here is a list of suppliers.
Personal experience covers only a small number.
There can be quite a bit of variation between suppliers. But even some fairly good suppliers can have spotty quality control. From one supplier, both the first and second shipment of an uncommon shrub rose was a slender green cane in a 2 inch pot, lacking leaves. The pot had perhaps 2 inches of soil in it and the roots were nowhere to be seen at the small surface. This is because unlike grafted plants, own-root roses do not yet have a size standard against which they are compared before shipping.