I purchased one of these a little while ago, and the paint has yet to become damaged thanks to a few layers carefully added over a few hours.
As for the assembly, it was rather quite easy and efficient! Although I would recommend not assembling the entire kit in one go before painting.
The best results I had were when I assembled the top portion of the kit in it's entirety and part of the frame but abstained from attaching the finer details until after the priming stage, as I painted by brush, or after aerosol or airbrush painting.
For the painting of these finer details, I highly recommend painting them still on the plastic sprues, as they can be quite easily lost or misplaced followed by minor 'touching up' following their attachment to the model.
As for the performance of the kit, it rolls fairly freely considering it's age.
Over-all, I have to agree that this is one of the best wagon kits I have come across for this prototype.