I think you have done a good job, i don't like the colours but thats all down to taste, but the actual quality of the joins and finishes is pretty good. Keep at it and you will get better, painting takes alot of practice to see what works best with what and colour schemes and stuff, i have been painting since the day forza 2 came out and im still discovering new quicker ways to do things etc. it takes alot of practice but you will get there.
If you want anything painted, or some tips or anything let me know.