Adrian: I'd go with the Porter.
I expressed my satisfaction here when I brought back my 18-month old Ridgid 12v lith driver and they just gave me a whole new kit. The new one died a few weeks ago, at 6 months (both times, the trigger function).
Now, the deal is that they will repair it for me for free. It's a 4-week (min) turnaround, so I had to go and buy another one (NOT Ridgid), to use while I wait.
It's like a 7-year power-train warranty on a 1980's Chrysler product.
Harbor Freight: Where it's always hard to put a price on worthless.