I have only 2 "U" hostas, the old favourites - the Undulatas. Both were acquired in the 1990s. UA is permanently mired into the root system of my Linden tree although I've managed to dig out one of the 4 clumps I used to have. I still have 3. And like Pieter, I've sampled them as a vegetable. I'm not a particular fan. Here are some pics. I'll post more than one of UA since I have 3 clumps.
A note for any newbies here. Since my pictures show these plants in bloom, note that the flower scapes have small leaves on them. That's one characteristic that can help you distinguish this hosta with white margins from others. Also, it never (or extremely rarely) sets seed.
To the right of the second picture, you'll see a smaller hosta with a white margin. That one just appeared, first of all as an extremely tiny plant. Then it grew. I ruled out its being a seedling because it's variegated. Then I thought it was UA, but when it got large enough and bloomed, its scapes were totally bare. I've decided that it's 'Francee', a plant I had previously grown in that location, but dug out long ago. I think there must have been a tiny bit of crown tissue remaining which eventually grew.
'Undulata Albomarginata', July 16
'Undulata Univittata', July 16