I really liked all of the VF3's that I have had. Much more than the VF4 and VF6, they tore up my back loading and un-loading. I'm not sure what vintage you are looking at, but I have a warm spot in my heart for the ~'98 we had once upon a time. Best Haas I ever ran.
Three issues you are going to run into:
Power. These draw quite a bit of power. I hope from your user name, you have an abundance of 3 phase. If you have 240 volts, it is a pretty simple and relatively inexpensive proposition to get a bump or boost transformer. I had to do that once and it wasn't too bad. If you need to get a phase convertor, I think Phase Perfect can both make your third leg and bump up the voltage.
Door/ Ceiling height. Since you said garage, I am going to assume standard garage door. If it is only 7-8 foot tall, it can be a large undertaking to get it under the header. Plan on doing some construction. Secondly, depending on you ceiling height, you may need to do something with above the Z column. At one place, I had to build a dog house above the column to allow it to go all the way up. Wasn't to bad to do since I just roughed it in with a sawzall and then had someone do the drywall.
Cement thickness. This is a wild card that I never worry about, but probably should. With this machine, you are probably over what a residential slab can withstand, according to the books. Then again, I don't know anyone that has actually destroyed a slab so I don't worry about it. You could be the first.
