I have bought quite a few things from them.

220v dual mig welder (gas or flux) - used countless hours on body work and has yet to fail me (I did get a year free replacement when I got it so if it does decide to go on me, I will just take it back
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=94164

4.5" electric grinder - used to grind down the welds from the above welder, once again still running, no problems
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=91223

3" air cut-off tool - used many many hours, still no problems, I just make sure to squirt a shot of wd-40 into it before I use it.
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=47077

air powered angle die grinder - also used many many hours without any problems, like above I give it a shot of wd-40 before every use.
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=93088

air shears - no problem except it needs a set of replacement shears, broke during regular use, normal wear.
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=36568

and last but not least
hvlp spray gun - used on everything from primer, high build primer, color and clear with no problems. Used it to paint areas that will not be seen much, for a more quality paint job for exterior paint I bought a expensive hvlp gun, but for places that barely sees the light of day the hf gun worked just fine.
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=43430

the one tool that I did buy from hf that failed me was a set of ratcheting wrenches. 2 out of the 7 in a pack just froze up. I half way blame that on myself for using them to break bolts loose and over tightening.
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=96654

Ive had good luck with the their tools so far and I will continue to get things from them until I see different. Most of the tools I bought from them I only had planned on needing once or twice. They far exceeded my expectations. Tools that I can see needing down the road, I go else where and pay more. Id rather spend the money saved by buying hf tools, on parts for my truck, which will get used alot more than the tools that sit in my box.