I'm very happy with tubeless, to the point where, if I was somehow forced to ride a bike with tubes, I'd feel far less confident and worry about punctures, I'd imagine.
10,000km and no deflation issues. A little over 8,000km of that was on the first set of Hutchinson Sector 28s. Comfort-wise, they're much better than the tyres my bike came with, probably due to slightly lower pressure (as I'm new to cycling, I have nothing else to compare to). On the basis of that longevity, I don't think they're expensive tyres, per distance travelled.
All four I've fitted were easy to get on. I wouldn't use them other than on tubeless rims though - Stan's Notubes Grail in my case - and the two I've taken off were easy to remove too.
In summary: a strong endorsement with no reservations.