I use the same tanks and reels for B&W, C-41, and E-6, with no serious problems from chemical buildup. The worst is that my plastic reels (I mostly use stainless steel, but I do have some plastic reels that I sometimes use) slowly become harder to load, perhaps because of a buildup of residues from final rinse or Photo Flo. Scrubbing them with a toothbrush and scowering powder once in a while helps a lot.

If you're used to B&W processing, E-6 isn't really any harder, although if you use a 6-bath kit, it does take longer, both for the setup and to go through all the steps. The worst of it is temperature control. The idea of using a roaster for this is one I've not run across before, and I may look into that myself. To date, I've used a dishpan filled with water at slightly above the target temperature. That brings the solutions up to the desired temperature pretty quickly and keeps them stable enough through the most temperature-critical steps. I've not done scientific measures of color accuracy or whatnot, but the colors I get seem fine to me.

I've used both the hobbyist 3-bath kits (Paterson Chrome 6 and Freestyle's Arista kit) and the Kodak 6-bath kit. IMHO, the Kodak kit produces noticeably better results. The Kodak kit is officially single-use, and I use it that way (I don't re-use chemicals once film's been through them), but the 3-bath kits all seem to recommend re-use. I've never been completely happy with the second or subsequent passes through these kits, and even the first pass doesn't seem to quite match the Kodak kit's quality. Others obviously disagree. Even with re-use, the hobbyist kits are a bit pricier than the Kodak kit, so the only advantage they've got is that they're quicker to use. Unfortunately, the Kodak kit is getting hard to find, and there are rumors it's been discontinued. One Web retailer that still lists it is Minilab Supply Store, but I've never ordered from them; I just stumbled across them and bookmarked them for future reference.

Edit: For those in Europe (and presumably Japan), Fuji's got a 6-bath kit that looks similar to Kodak's offering. I've never seen a US retailer that sells it, though.