[zfaylor]

I have a 906-1 with an 88hs. I LOVE mine. There is a fair bit of difference between the 88 and the 88HS. Don't expect to do much 3d surfacing with the 88 controller. We drip feed ours 100% of the time and it does fine unless we get a file with 50,000+ lines of code and it can lag on some of the abrupt 3d moves.

The 904-1 is a good machine. Only downside to them is they generally have linear rails instead of box ways like the 906-1 (4020) machines. They are robust machines and every part on them can be purchased still. Easy to work on if need be as well. Our monitor took a chit in transport. We had an LCD upgrade the next day and we were up and running. The LCD screen is so much nicer anyways I wasn't too upset.

As for the 88 controller. Do not worry. If you fall in love with the machine you can do the Calmotion controller upgrade down the road. It is pricey at $8000 IIRC but it transforms the machine drastically. New controller and screen brings it into this century.