No probs. The Demon is simple to work on now there is no QEV. Take a look at my guides for HPR and bolt maintanence in the VG section - that is all you need to know now. No need to take marker apart to fix qev as there is none with this
I loved my GEO2.1 when I had it, and know what you mean. I am trying to be unbiased - but both markers shoot about the same - Demon a bit smoother and better efficiency now.