If you are doing alot of shooting go with the shoebox set up. I keep a couple 80 scuba tanks and a pony bottle, for remote fills, topped off to fill guns from. I also have a 12 v portable compressor that stays in my truck for when ever I might need it.
If you get the shoebox you really should get a tank. The shoebox is slow but very reliable and is in fact my next purchase to fill my 66 CF scba used tank I bought off ebay. It passed hydro testing with 4 years left on it's life but by the time it can't be filled by a shop I will be filling it myself. It comes down to do you want to have to drive back and forth to the paint ball shop or be able to take care of it at home. For me to get my tank filled I have to drive almost an hour each way. Can't advise about the nomad as I've never had one. I use a yong hang copy called a vevor and it has been a pita but does fill my 191cc Liberty very fast. Bill, (can't remember his handle on the GTA) has one to fill his rifles and hasn't had any problems.
I may be wrong, ask my wife, but i believe the "step up" compressors need an oil less shop compressor so there is no chance of it getting into shoebox or rifle.I would go with the tank and free refills for now, and if the time comes, you could sell the tank and buy a compressor.AOA has a calculator that will tell you how many fills you'll get from your tank.
All I have to say is.... there is nothing like air independence.I have the Vevor.. I fill guns directly.. Not sure what hassle you are referring to.. Fill a 5 gallon bucket with water, plug in the pump and fill your guns til the cows come home. It takes around 30 seconds to top a gun off to 3k. That ain't even long enough to build any heat. The compressor is compact and easy to take on the road where ever there is a power supply. It will cost you less than $300. I will absolutely buy another when and if the time comes to replace it.The hassle is self inflicted when you start asking the compressor to do things it wasn't meant to do.Free tanks fills would be nice... as long as it's convenient. All tanks need periodic inspections.