I have a TP unit, and a Harbor Freight unit. both work fine for me. When the HF gun wears out, get a replacement gun from TP Products. I bought 3 guns from TP, just to have spares when I need them. I have had both units about 8 years, and no problems. The TP set-up came with the dual stage filter can, but I just use a cheap $ 40.00 shop vacuum for the HF unit. Much cheaper than the dual stage filter can, and you can buy shop vacuums all over the place when you need it, no down time.