I have a propane oxygen system. I am not sure it is cheaper, though cheaper is part of my motivation for getting it. It's cheaper if you already have a propane tank for some pupose, and those tanks are somewhat cheaper to start with. But apparently propane uses up oxygen at a much more comsumptive rate. I forget though, some rocket scientist had an answer as to why that wasn't a problem. The good things about propane are that the gas is cleaner burning, both less sooty in the shop and less dirty on the work; it is colder, acet. is clearly too hot for this kind of work, 98% of the flame is just blasting the air all the time, though at the end of the day that probably doesn't really mater since people use it just fine; Accet is a safety nightmare, the training video is called "1000 Ways to Die". It really has no place in a home shop, as far as I am concerned. Whether propane does or doesn't belong, at least it is an everyday product around the home.
As far as cost is concerned for rigs, if you already have propane, then you only need one more bottle to run PO, no worse than one bottle of Accet. Whatever unit you try, you could use the same gages. I would only get good quality ones, for a host of reasons. That leaves the torch. The Meco torch is pretty cheap, and one of the nicest, though it probably doesn't handle quite the way a Smith does with the candle handle. Still, if you are outfitting a home shop the Meco is probably more versatile since it works very nicely for a little welding in many metals, has cheap nozzles you can switch, propane and accet nozzles, and so forth. Very nice little rig.