[hope]Kaizoku-Manga will happen one day, you'll see![/hope]
For volumes 1-21, all there really is are the old Mangascreeners scan. From volume 21 through volume 50 (with volumes 26, 27,28, 40, 43, 46, 47, 48, 49, and 50 done as tankobon scans, with more tankobon scans of old volumes coming in the future, and all of Null's new volume Edited Mangas will be tankobon Edited Mangas.) These are all available through IRC, but you'd have to find Null's website and channel yourself. They like to keep their existence secret, which is why they ask that people not link to their site.
For everything after volume 50 (that's chapters 492-518, as of the time of this posting) there are alot of options. In terms of translation, they basically all use Carlos Net's translations, so there's no difference there. However, there are VAST differences in picture quality. In terms of best picture quality, I would say that it's between OPHQ and Binktopia. I personally favor Binktopia, since OPHQ's releases were at one point rather sporadic, while Binktopia's were consistent, and I got into the habit of using their scans. I also tend to prefer their picture quality a little bit. However, there are a few chapters near the end of the Sabaody Arc where Binktopia used alot of different fonts in their Edited Mangas which was a trifle annoying, but they seem to have stopped that now. Overall, I'd say that you're fine with either Binktopia or OPHQ for chapter scans, and should archive (and reread, since they do their own translations) Null's tankobon Edited Manga in the end. That's what I do, at least.