I agree with geordie85. I've had 2 aps-c camera's and bought a full frame and never use the aps-c any more. Reduced noise is a huge plus. I use mine on an 80mm triplet so it is a fair bit undersampled but as I use Pixinsight I can drizzle the stacked frames to double the resolution quite easily. I'm often surprised at how good small objects like galaxies turn out.
I've bucked the big 2 and shoot a Sony A99, you can check my results in my gallery here. Just bought my first cooled mono cam + filter wheel and filters so waiting for the compulsory cloud to clear up before testing it!