We've got one- only had it 2 months, but we've just spent 3 weeks in France and Italy with it, so think I've a fair idea of the good and bad points.
Bad- it's shorter and narrower than a T4, fuel economy won't get over 30mpg on the motorway at 70mph, 22-24 around town, there's a fair bit of body roll and the free top version is 2.1m high so won't fit into most multistorey and height limited car parks.
Good – they're pretty reliable and well made, come with aircon, will sleep 4 at a pinch, have proper seats and belts in the rear, the size makes them easy to drive round town, and if you get the configuration with the back row of seats which split then bikes will fit in without removing the wheels, so plenty of room. Freetop lets you sleep inside with the bike downstairs as well. Seats are honestly more comfortable than our Mazda 6, though if you're over 6'3 you might run out of fore and aft adjustment. Will cruise at 80 but economy suffers.
We paid 3800 for a nice 'N' reg, 4WD and free top, waxoyled and rust free. Wife and kids think buying it's one of the best things we've ever done- we hardly use the other car at all now, and will probably sell it.
Bongofury is the main place to learn more (and most sensible place to buy one). It's very friendly, has loads of buying and running advice. There's a few mountainbikers post on there, normally some sort of a bike related thread going, and plenty of people will offer buying advice or look at vehicles for/with you etc.