Nothing like argueing a subjective question. I think it's more a matter of what turns you on personally. To do it well takes great skill, but few can do it to the level of an art, at least as far as I'm concerned.
At the University of North Texas I heard a lot of jazz and a lot of terrible improv. I lived in Bruce Hall, where they put a lot of musicans, so I heard it in the lobby and from their rooms almost daily. The one o'clock band, a jazz lab reserved for the top players, was quite something, in fact they were consisttently fantastic as a group, but even so the improv was hit and miss, sometimes great, but often nothing to write home about. Regardless, if they still play on Friday afternoons at one o'clock in the student union building, and you're anywhere near there, go and listen. It's always a treat.
Improvisation is a different skill from playing something as written, and a bit like comparing apples to oranges, if you ask me. I found a lot of jazz students seemed to almost worship at the improv altar, as if anything else was utterly inferior. I can enjoy it for a while but much more enjoy Beethoven's Fourth Concerto.