I've been using my Omaga Trail Charger for some months now, in the beginning I timed fill times which average three and a half minutes with the 470cc Bobcat and 480cc of a Wolverine a minute or two longer but not filled very often. Using a pen stroke every fill I was surprised how fast time accumulated...Gave the grease pot its first rotation...Those pen marks represent about 10 tins or more of shooting, no doubt more than that...not counting my springers. This little unit works flawlessly. Unable to hand pump any more I am a slave to tank or compressor if I want to shoot PCPs...I do! I worry about this units longevity...time will tell. The GX CS4 I unit has caught my attention recently and plan to learn more about it...and may get one if I can find one....but for the time being I really like the Trail Charger. 
..Need to order more pellets but that's a good thing!
