There are so many wires on the market today, that run on different processes.
You have to read the manufactures specifications. Strength is one thing, deposit rate is another.
I've always thought dual shield, (flux core gas coverage) was very fast for all position work. For most of us here dealing with just mild steel, just about any wire or process will have plenty of strength.
I think where most people get into trouble with wire feeders, is they do not run them hot enough! It is so easy with a Mig welder to get a beautiful looking weld, and yet have no penetration! Mig welders are notorious for cold lap, I'd much rather see a little under cut on the toes of a Mig weld than cold lap! At least then I know the weld has bitten into the base metal.