Having had both, a stand alone stuffer is way quicker if you plan on making big quantities.
The combined ones can sometimes struggle and as a result the meat heats as it's minced which spoils the texture.
If you're getting a butcher to do your cutting, ask them to make you mince for sausages (80% lean 20% fat) and pack in 1 or 5 kilo packs then you can freeze the majority and defrost/make when you are ready. Commercial mincers make short work of mincing 10 kilos of pork - you'd have to have a couple of hours spare to do that with a little mincer/stuffer combined.
I used mine twice, maybe 3 times before getting the stand alone one.
HTH