What I've read in this thread is that no progressive press on the market really deals with the case problems centered around the primer. My Dillon 650 deprimes OK, but so did my Lee Pro 1000s. But there's no way to inspect or determine what's in those primer pockets, and although progressive primer seating mechanisms vary, none are completely satisfactory (at least none I've used). There's no way that seating on a progressive press is going to provide the same "feel" for a primer seating correctly that will be obtained with a hand press, or, preferably, a hand priming tool (I use the RCBS).
What I can derive from this thread is that loading on a progressive from primed fired (and cleaned) case is fine for plinking ammo, but that for "real" (match, defense, hunting), it's best to do all the case prep first.