I also own a 10″ Altair Astro (GSO) RC. I understand that Altair made some kind of modification to the GSO RCs before selling them. I think it was something to do with the mirror cell but I don’t know exactly what. They have stopped selling them now.
I’ve done collimation once and it was a bit of an ordeal. I expect it is one of those things that once you have done it a few times then it gets much easier. I’ve found it to be very stable and appears to hold collimation well. Though as I am also using it for spectroscopy, I don’t worry too much about having the collimation absolutely spot on as this won’t affect the spectrograph resolution, just the throughput and so SNR.
I also upgraded to the Feathertouch Focuser and found it to be rock solid. I’ve not bothered with a motorised focus as I am in the observatory and I can tweak the focus if needed. Though I find the whole telescope and focuser to be extremely stable and so I rarely need to adjust it, except due to seasonal temperature changes.
If you get a 16″ then I’ll be very interested to hear how you get on with it. I wonder about one day upgrading to a larger GSO RC. Though for me the choice was also about a compromise between matching the focal ratio with my LHIRES III spectrograph, and keeping the focal length short so that I have a reasonable field of view in the guide camera.