For someone who's "not that interested in CO2" you've certainly been making some great, interesting posts on that topic recently. Thanks
My feeling is that the QB78 platform will remain the CO2 tuners and enthusiast's choice in future due to the complete modularity of the design. The XS60C is not so easy to customize, but I believe that in "Version 2" it will offer a great alternative for CO2 shooters who don't want to mess with the gun too much.
Like you I was not too enthusiastic about the Al receiver, but maybe there was a cost constraint there. The XS60 "Version 1" certainly had more - and more complex - parts than does the QB78 (many of them in the safety mechanism), all of this adds to manufacturing and assembly cost. Machining the receiver out of steel would have been yet more cost. To keep the selling price of the XS60C competitive with the QB78, I think Xisico made a creditable effort.
I'm told that a re-design of the safety mechanism is involved in the new version of the XS60C. That's a good thing. As you say, this has to be treated with great care in "Version 1" guns and it's the reason Archer Airguns did not sell that product.
But I'm still excited about what "Version 2" may be, when it comes...
Archer Airguns Inc.
Online stores http://www.archerairguns.com