I've got Timolgra's old 450 and use it for green laning, I have a 40 min road ride to get to the lanes.
I think I've had it two years now and so far it's been dead reliable. The only issue I've had is once the rad overflow did it's job on a very hot day and me having just done a long section of nadgery slow stuff (there is no fan but I think you can fit one if you want)
It only holds a litre of oil so I change this and filter every 3 rides (that's a full days riding, road and lanes, and roughly 150 miles). They are supposed to be done every 10 hours, but that's race use so I'm guessing every 450 miles is about right for road/laning use.
The electric start is supposed to be marginal but (touch wood) I've never had an issue (you can buy upgrade kits though).
What else can I say...........well...............the bike has a vicious and fun top end but can trickle along a trail no probs. It's incredibly light and it is a thousand times a better bike than I am a rider. It IS basic but is an absolute hoot to ride and has real 'character'
Andres
Edit: Oooops, didn't cotton you you meant the 'new' Bergs