Spot Welder?

Anyone using a spot welder like the Harbor Freight unit or something similar? I'm about to do full quarters, tail panel, trunk drops, and a roof skin on my E-body and I'm curious if one of these hobby type machines is worth it? Will be somewhat limited for what it can reach compared to a bigger machine but might be better than plug welding in some areas? There's a used 120V machine near me or I could get a new 240V machine at HF the next time they send a 25% coupon.