After a bad experience with some tainted co2 at a local field I decided to upgrade to HPA. After checking the reviews on pbreview.com I decided on this system. I picked one up for $58 on ebay with $10 shipping...a great price. I downloaded the user manual from airamerica.com. When it arrived I stripped the reg and lubed it. I've given it a test run this past weekend, shooting about 5,000 rounds. It worked flawlessly. Those familiar with the A-5 know it can be temperamental when hooked up to HPA. Not with this tank. I could actually lower my output to 550 psi and the marker would still shoot at 275 fps and the cyclone would still work. Actually it worked flawlessly from 550 to 900 psi. For those of you that have a stiff on/off valve I say take your valve apart, clean it and lube it with lithium grease like the service manual says and it will be smooth as butter.
The regulator is pretty heavy. In fact the carbon fiber 68/4500 tank and regulator weigh more than my 24 oz steel co2 tank and would be pretty cumbersome if mounted on the marker. However, it works just fine from a remote.
I wouldn't waste my money on a new fixed pressure HPA tank when I could get a used Air America Apocolypse for less than $100. Even if you needed to spend another $100 on recertification and a total rebuild...which there is no way it would cost that much...you'd be much happier. Especially if you own both a high pressure and low pressure marker, or plan to upgrade to one or the other in the future. This tank will work for both.