| I used Ultraflex for a while (two or three sets in a row) before the 'old man' retired. I haven't liked them since. The bottom three seem dead-ish and the G string is untolerably nasal, both pizz and with The Stick, and stiff feeling.
The pluses are that the winding has a neat surface that gives you a bit more feedback through the left fingers than the glassy winding that, say, Spirocores have, without being grabby. The pitch on strings is very good, but different than whatever strings you are using. It'll take a few days to figure out where all the notes moved to. They seem to last a good, long time.
Maybe the new guy has gotten it more together now. It's been two or three years since I've had a set on. | 
