do you have an eta on 2.0 final

No, sorry we do not. We're working as quickly as possible to get to a Beta 3, RC, then Stable (possibly another Beta after 3 depending on what we put in). Upgrading the backend is taking longer than expected. Note when we do reach stable I will still need some time to get the various integrations upgraded.

When I click on a profile there is NO way I can actually get back to that selection.

Will that be fixed with 2.0?

Possibly, the filters now properly have names separate from actual field names of a user so it should be easy to send those values back without it causing any conflicts like it does now. I'll know more once we get all the filters put back in. Ideally it should probably keep in memory (session? cookie?) the values you selected so it'll always re-display the same until you clear it.

Do you plan to have a demo site for non developer members to check out at any time in the near future?

We'll update our demosites to CB 2.0 once it has gone stable and the various plugins are ready for it. Professional subscribers will receive a build of CB 2.0 before we go stable.

How many images? Which default sizes has the new gallery (tn, full)? I assume JPG? Or does it also take transparent PNG? (that would allow nice variations by CSS background color )

PNG with transparent backgrounds would be best so we can do a deep compression on them and also have customization options. JPG with white background and good compression is also nice, but you don't need to worry too much about the compression as we can handle that. Ideally the full size images should be at least 200x200 (thumbnails as 100x100); they absolutely need to be squared.