I have 4 HF jacks, from 1.5 tons up to a 4 ton, the oldest one I have is over 10 years and if you have seen any of my posts over the years, I beat the heck out of them, especially during the winter and I have never blown a seal, cracked a handle or lost a wheel on any of them. I have no problem with them and they have been good jacks.
Does Harbor Freight have some junk? Yes, just like any other company and they have lot of good stuff for the average home mechanic and some of the NASCAR teams are using their Daytona brand jacks at the races every week.
Just because it comes from a Harbor Freight does not mean it is automatically junk, just like every single other company out there, things have improved over the years.
By the way, the Costco unit that Sam posted is made exactly like and by the same company that makes many of the HF jacks.