[totaltec]

Brett Brewer! Welcome back man. I learned a lot from your posts when I was first getting started with XC.

I am biased toward the responsive skin. I spent weeks/months testing it, and I am sure it is 99% bug free. Ideal comfort is not a bad choice either. Of course if you want the most control possible, just work in the 3-columns skin. It certainly will be the most familiar, and it has the lightest payload in terms of code and file size.

I usually either start with ideal responsive, or 3-columns. It depends on how custom the job is. If I want something quick I use ideal comfort, since responsive design always takes more time. If I want something quick and optimized for mobile I use ideal responsive. If I want something truly custom, I start with 3-columns.

Formal answers to your questions:
1. Not sure. The major difference between when you were around and now is the template system itself.
2. Bug free? Probably 3-columns. None of the skins are HTML5.
3. I'd say Ideal Comfort / Ideal Responsive.
4. No other default skins are truly optimized for mobile, I think ideal responsive is pretty good in that department.

There are also some nice looking 3rd party templates out there, but most of them are bloated in my opinion. That's my two cents, hopefully we'll get some more feedback from the rest of the guys. Good to hear from you.
-Mike