Just become a convert and got a Trek Powerfly FS 5 after years of moaning about them - mainly due being old and unfit, but then going out with people older and unfitter than me who had one that kept scorching off up steep hills without me
Only been out a few times but seem to have accidently found a whole new way for ramblers and dog walkers to hate me!
Have been polite and courteous (so far!) but they look even more grumpy and resentful in return than when I've seem 'em while out on a trail bike!
I guess when you think about it they've about won (or think they have) the battle to prevent motorbikes accessing the countryside, and we go and move the goalposts by using devices that get around the rules
That alone is reason enough for me to get one