I had one a few years ago. It rode fine but not as nice as non-folding bike of the same price range. It sounds like you could use the folding feature a fair amount which would make this bike nice. It will not ever ride as nice as most non-folding bikes of the same price range.

I would not recommend buying a frame and building it up, unless you have parts already on hand. Most times building up a frame will cost alot more than buying a complete bike. I also would not recommed putting alot of money into upgrading parts as I don't think you will gain much of a ride improvement on that frame.

It is a pretty nice riding folding bike for the money.