If you do buy a E3 make sure you get the control panel you want with it. They are kinda hard to find, at least not all "extra hole" drilled out anyways. Thos single player Atomiswave panels with the card reader are total BS. The monitors are also said to be rather poor at 15khz, but fine at 31khz... Having never seen one first hand I can't say if this is true or not, be aware is all I'm saying.
Blasts are very very easy (comparatively speaking) to get parts for. The monitors are the biggest problem with them, so make sure you get a Nanao 2930 manual sync chassis. The 2931's get the black goop of death! Ask Lemony how long his auto sync lasted, I think he said one day after pickup it died. They all have convergence issues as far as I can tell tho, but with a little work you can fix this with home made strips applied around the back/under the flyback. We've got a thread about it in Arcade Central, check it out.