Not similar.
Is it that one from harbor freight that's 'supposedly' a DA, but looks EXACTLY like a rotary?
If it's 7" and DA, it's not gonna do a dam nthing but rub **** around. 7" is way too big for 90% of paint work unless it's a rotary. Rotary's have the availabale RPM's to make up for it.
Like weems said, ditch it and go the right route.