I have one, and overall I love it, but it does have niggles:
the harness straps are crap, and really fiddly - also, there's loads of strap left loose, so dd1 chews it all the time
the recline on the second seat would be a problem for ay average sized child - dd1 is 19 months, but tiny and I think she is finally a bit too big for it (haven't checked recently - she doesn't sleep much in the buggy anymore)
the brake is really stiff - so much so that I find it hard to put on/off if I only have dd2 in the buggy 9as she is so light)
I too have found the material is fraying in places - i am not particularly precious/careful with it, but neither has it had hoards of elephants tap dancing all over it. I have been using it for 15 months now, though, so i guess not too bad.
It is not very warm/padded - you'll need decent cosytoes/lambskin/snowsuit as applicable. Even the main seat is quite drafty.
BUT, I still love it. imo, it is the best thing ever. It does have it's drawbacks, but nothing else beats it. dd1 still fits in (4, and tall/big for her age), and I can get a fair bit of shopping in the basket (although that is likely to get squashed these days if d2 is in stamping mood)