Sensitivity is pretty important.. for me, anything that peaks around the 50% mark is acceptable... I'd love a STL11000XCM, however at 32~33% QE in Ha it would be a camera that would require you to do megadata images to get good detail...
I used an STL11000XCM for about a year and a half. I loved it. Lots of fun. One shot colour has its advantages for sure.
http://www.pbase.com/gregbradley/image/79670650
Yes the ST4000XCM is getting great results but the king of the one shot colour game still seems to be the MX25C in my opinion.
The STL didn't really require super long exposures. Depends what you wanted to image. If you were trying to get dust areas you'd get colour noise being a problem. If it were a bright object (like 80% of all images posted) then it worked really well.
Main problem with these large chipped cameras is a scope that has a large enough (read that as 45mm -50mm minimum) corrected field.
That limits it a lot to FSQ106, AP, TEC, Taks with 4 inch focusers, some Newts with 3 inch correctors etc etc. Not a lot of choice really.
Greg.