This is the biggest, strongest, best excavator kit in the world!
http://www.vario-earthmovers.com/
Certainly not the greatest for "detailed", but the price reflects that too... besides, if you like scratch building, then you got a good platform with this model to start. I think this particular model's greatest asset is that it comes as a kit that "you" have to assemble/paint yourself. It's getting to be a sad state in this construction equip hobby that the norm is now becoming RTR only, and some of these model companies haven't freaking clue how to build their own models either, leaving you with a defective non-running model right out of the box.
I have this hoe, I've been working the shyt out of it for 5yrs this month, I've had very little trouble with it, just minor upkeep.