Got a set on my TC. Didn't take too long to fit (although they are pretty tight, so there was more wiggling and swearing involved than I expected). They do feel like you'd have to slide on them for quite a distance or hit them quite hard to take them off... by which point (as you mentioned) bars probably aren't going to make much difference either.
The only advantage I see for bars is if you are off-roading because you'll lay it down fairly frequently. For road use I'm less convinced. My only complaint with the X-Heads is that even though they are really nice quality, they are bloody expensive for a couple of bits of plastic.