Shoebox vs booster?

One huge difference is, (along with you shop compressor for the first stage) the shoebox pumps up air. The booster only increases the psi of the air you have on hand, generally requiring a minimum of 500psi input (your shop compressor likely will not hit 500+psi so you still need high psi airtanks).
Google air booster's no shortage of videos & such.
John
 
I've not had any experience with a booster but I do have a shoebox max. I think I would reccomend the compressor over the booster because I like to be able to fill my tanks. I've also not had very many problems with the max either you might need to replace an o-ring every once in awhile but that's about it. And my shoebox gets HEAVY usage. Also since you have two tanks you could have an adapter that goes from the tank to the gun and then another one for filling the other tank so then you basically have air 24/7. Its really nice to be able to fill your own tanks and it doesn't bother me how long it takes either, from zero I can just pretty much turn it on and forget about it for the rest of the day.
Leo : )
 
The Shoebox is very easy to work on and the parts are inexpensive. Not sure the same could be said for those boosters. You can use even the smallest shop compressors as long as they have a tank. I have the smallest Senco model. About $100. works great! If you keep the Shoebox properly lubed and keep the belt tight should have no problems. The compression cylinder o-rings will have to be replaced at some point. but its not hard and they have videos on their site on how to do it. 

Also it looks like you will need more parts to make the booster work. Air fittings bleed valve maybe make a stand or mount for it. The Shoebox is designed for this purpose. The only thing extra that is recommended is a moisture filter on the input line. 
 
The Boosters do not need a large compressor, I have one of the small very quiet compressors to run mine. It allows you to use a much larger quantity of air from your scuba tanks before they require refilling. Unlike what might have been said, Boosters are extremely simple, there is a low pressure high volume chamber and a small high pressure low volume chamber. It takes a couple of minutes to take the booster pump apart to service it, very simple design. I have just bought an Omega compressor to fill my own scuba tanks which might be overkill since 2 full tanks using my booster pump will last me almost all year. I do not use a huge amount of air, just for testing LDC's on guns before I ship them. I have had no issues with my booster pump and have owned it now for about 2 years. The booster pump is very simple to operate, you attach low pressure air to the main cylinder and a scuba tank to the high pressure cylinder and the gun to the high pressure cylinder, then operate a lever that pressurizes the main cylinder, this cycles the small cylinder and pushes high pressure air into the gun. It takes very little time to fill a gun, depending on the size of the air tube I can go from 2000 psi to 3000 psi with only a few actuation's of the pump. They develop very little heat or moisture, but you do need to make sure that the air being fed to them is also moisture free. They are a great alternative to owning a high pressure compressor, if my dive shop was more reliable I would not have invested in my Omega compressor, but it has taken anywhere up to 3 weeks for me to get my tanks back from them before so I had to get my own source of air, Neil.

30 cal my booster came complete with the hose and gauge to attach to the gun, all it needed was air fittings to fit to my air compressor, which most air operated units require because the maker has no idea what fittings you use at home.It takes a couple of minutes to assemble the unit for use when you get it, very simple. 
 
Your budget dictates what you can afford, but a good tank and a compressor is a must for serious airgunning. I have had everything from foot pumps, tanks, and compressors. A tank and a compressor is a must have. While the shoebox and omega style compressors will fill tanks, real hpa compressors are the only way to go. My shelden is probably at the lower end of true hpa compressors, but it only takes 7 minutes to fill a tiger shark from 3000 to 4500psi. I wouldn't want something that takes longer than that. For the cost of a shoebox and fill times, a real hpa compressor is worth the extra coin. Units like bauer, airmax, shelden, will fill very fast and go for ever before needing rebuilt. The fill speeds and longevity are worth every penny over the slow filling compressors that also need frequent rebuilds.
 
My biggest hang up about the shoebox is having to buy a good moisture remover.the shoebox at 650$ plus another 200$ for a good moisture filter.I've seen cheaper filters but uneasy about them so in the end looks like 850$ for a good shoebox setup. I just may look into a used paintball compressor. I have seen a few in the 1200 to 1500$ range gas powered.
Post up a picture of your shoebox set up if you guys don't mind to give me an idea of how a rdy to use set up looks like.
Thanks