I have a 330a/bp also. Fantastic welder. ENORMOUS power. maxes out at something like 450A.
I didn't see the price on the ad, but i gave 300 for mine and felt like it was a very good deal.
I like that it can be repaired with a service manual and a voltmeter. No expensive boards to go bad.
It's SINE wave output though, and aluminum welding can be a little tricky to learn on SINE wave machines.
Full output requires about 105A 230V input. So it's a bit of a power hog. It's a 900lb welder though. It does well
if you just sit in a corner and not move it. the foot pedals are a bit rare and go for about 150-200 on the bay.
No bells and whistles. Runs an arc-air well and won't kill the machine.
I traded up to a syncrowave machine, but there's nothing wrong with a 330 and they will work forever. there's nothing
inside them to go wrong. If you want portable to take to a buddy's house, get an inverter and just pray a board doesn't go bad.
I kept my 330 as a backup machine because i know when the syncro loses a 500 dollar board, the 330 will work.