Hi OXY,
Yes it's got every feature you could want for an older unit. We also have a couple syncrowave 250's with the water cooler attached to the bottom. They are about 5 years old.
The thing with the 350 is the noise it produces with that cooling fan always on. Annoying when trying to hear my radio. The newer syncrowaves, I believe they have a thermostat that only kicks the fan on when the transformers reach a certain temperature. Thus you barely notice it's even on.
But I do love my 350 because of the power. As far as control I think it has great control. I weld a wide range of materials and thicknesses.
It never gives me a hard time and its very dependable. I have to maintain critical weld tolerances.
I'd say the syncro 350 would probably suit your every need. I'm not to sure about pricing for, say a used one. Mine even has one of those wire feeders that you might use with a CK attachment. Never use it, but have the feature.
If I had my own home shop then I would be more than happy with the 250. Both the 250 and the 350 are fine machines.