On the HB expensive one you cite.... can you give us the model number or sku ?
What counts is the type of vacuum mechanism the unit has .... your post might leave someone to think that once they get one that works properly for its design that it also fills the bill for our AC work... but again, it is dependent on the type mechanism... and I do not believe ANY venturi type can pull the necessary vacuum to do the job effectively.
I got a $340 HF 14 inch band saw on sale for $260 a while back , put link type belt on it , when I started it up I did not even have to track the blade. On the other hand , got a right angle slow speed water grinder and found they had not put any grease into the 90 degree gearbox... works fine now though .