I know that both the old Jackson and Perkins and Weeks Roses tried to convert to selling own root roses and found that many roses that grew vigorously budded, were duds when they were grown own root. However, many of the roses were good roses own root, but gardeners had to wait a few years and allow the plant to mature before it could catch up to a budded rose. At that time, the customers wanted more immediate gratification, so the program failed for both J & P and Weeks.
Many of the roses sold in the last fifty years would have never made it to market had they not been budded. It was the industry practice to immediately bud any seedling they thought would make a good rose for testing. They were never tested as own root roses. Now nurseries are selling those roses as own root and they will never be as vigorous as the budded roses. But many of the roses would have been just fine had they never been budded. They were and are simply good plants and don't need the extra vigor of a rootstock.
I don't know of any nursery that is doing field tests of roses of own root roses these days, so it will always be a gamble to purchase an own root plant. Conard-Pyle, Meilland's US agent, is trying to move towards only introducing roses that will grow well own root, but they are not testing those roses in several different climates.
I am currently growing several own root roses that exceed the plant size given when the roses were registered, but they may be the exceptions Zuzu mentioned. I prefer budded roses in my climate because it is both colder and hotter than Zuzu's climate and I like having the roses take off faster. However, it is difficult to find good budded roses nowadays because budding is becoming a lost art. I have finally found a nursery in Redding that sells both Weeks and Meilland's roses budded and they are the best budded plants I have seen in twenty years. I don't know who the subcontractor is that supplies that nursery, but I do know if they don't carry a rose I think I want, I probably won't try to find it anywhere else.
I haven't purchased any roses from Palentine, so I can't really comment on their roses.
I planted 10 own root plants that Kim Rupert propagated for me a two years ago this spring. We had been waiting until the plants' root ball had filled a three gallon can before he delivered them to me last November. I potted them up to five gallon cans and had a friend over winter them in her green house.
When I planted the roses, the root systems of the roses did not fill the five gallon can, but were much larger than the one gallon can that most gardeners use before planting their own root roses in the ground. I'd say three out of the ten were as vigorous in their first season in the ground as the one budded rose I planted this spring. I think all of them will make it and won't be duds, but it will take a couple of seasons before they really take off. In this garden that's common. It takes about four seasons for a rose to reach maturity.
As usual, it depends on the rose. My budded Midnight Blue was a dud in this garden.
Just my two cents.
Smiles,
Lyn
