GX CS2 portable pcp air compressor thoughts?

The unique situation is with the 4 year warranty you get at least 4 years for $100 a year. That is a heck of awhile for an inexpensive compressor. I have never heard of a longer warranty on anything like that. Obviously not apples to apples by a longshot but the W31 is 2 years at $3000. 

I am not sure what the purpose of a self contained battery would be beyond being slightly more convenient assuming the batteries lasted long enough for your use. At the range you have a vehicle for 12V. At home you have your outlets. No good for camping or hunting as really impractical to carry very far and would scare everything for a quarter mile. It is an interesting configuration.