4000 miles just reached on my (what I assume is a 1st gen) Carerra Crossfirs e.
Everything still works, no disasters, minor problems included...
BB got a bit crunchy, I did a post on stripping, cleaning and regreasing the bearings, no problems since.
RD alignment came into question, I suspect my son clattered it sometime, manually re-aligned the hanger almost perfect since.
Battery cutouts were a thorn that kept recurring, solved (ish) by taping the battery to the holder while on the bike. Almost entirely solved the problem .
The all important battery condition...i sense it wouldnt do the original mileage now, capacity has almost certainly dropped off, but nothing concerning.
Wheels / hubs, still perfect. Still on the original brakes / pads.
It doesn't feel like a new bike anymore, its slightly rattler than when new but everything still good.