I am relatively familiar with these machines. The 611 (and 411, IIRC) are PC based, but use an old style 16 bit interface card to plug into the Hunter stuff. And the computer stuff is the old AT/XT style stuff.
If you have a computer hardware failure like the motherboard, it will be hard to repair. Hunter parts are long gone, or very expensive.
That said, the machines are pretty robust. The biggest weak point I have seen is the fans in the power supply (and the PS itself) for the PC and in the Hunter Interface box. You can probably still find a PC/AT power supply online if needed, and the Hunter one will be similar.
The DSP 200/250 heads are fairly robust though you need an old Hunter guy to calibrate them (and still have the fixture). If they are the wireless ones, the batteries can be troublesome and a lot of times, battery corrosion can cause other damage. They are balanced with the battery weight, so you have to have them in there, even when they die.
They used an early 2.4ghz wireless connection which can be flaky, but you can always plug the cables in.
The cables and connections get beat up pretty badly, but there are still plenty of them around.
With WinAlign, you can easily enter your own specs so that is not a big deal.
If its cheap and works, you probably can't go wrong. Parts can be hard to get, and the Hunter service Tech system is very protected, so if you can't find the local guy, or he isn't willing to deal with you, it can be a bit of a challenge. Conversely, people do sell parts on eBay and if you aren't using it to make money, you have time to figure things out.
When I first started out doing alignments (for profit), I did it on 411 and 611 machine(s) learned to take care of myself. I also tended to scour Craigslist for broken machines which I hoarded for parts.
I have moved on to an 811 machine, which is still not new, but Hunter still sells and services the major stuff (cameras and targets) and since the Hunter Interface uses USB to connect to the PC, it is fairly easy to keep the computer going (it is also Windows XP)
Feel free to ask any specific questions and I can try to relay any knowledge I have.
DaveW
