I say go for the Harbor Freight DA i have one and its works great especially after changing the grease to higher quality and using high quality pads and products.
I've gone one season using their pads which work OK, but the cutting and polishing pads on their backing plate barely last one vehicle before they come apart. This season I'm moving to a Lake Country 5" backing plate and their 5.5" pads.
The DA is great for the weekend warriors who only break it out a couple of times a year.