I am following the lead of Kripps, and building a scratch built bucket, too. It is slow, but that's because I work 50-60 hours a week and have a young son and a lot of other time commitments. I would think a young guy with energy to burn could bang one out fairly quick.
I personally am building it from scratch because I want this costume to be all mine. Everything will be crafted to me. I love Fett, but this is also a personal challenge. MS, BM, etc. all make absolutely AMAZING pieces, but they're just not for me. That stuff is theirs, and like I said, fantastic. Plus, I don't have the funds for it. My wife doesn't bother me too much about my Star Wars fanatism, but she would really get on me if I spent thousands of dollars on a costume!
It's all a personal choice. If you want the best, most accurate costume, certainly go with some of the stuff offered here. I doubt you'll be disappointed. If you want a costume just for you, give scratch building a go. When it's said and done, my bucket, before paint, will cost around $30, and that includes $15 for the batting helmet.
And I'm pretty sure everything on Fett was scratch bulit for the movie, so I think scratch built is MORE screen accurate!