Seems like you've done the tube thing and are starting to crave more detail and insight into the performance. Not that you can't get there with tubes(which the CAT Ultimate and Atmasphere MP-1(I'm assuming this is also tubes?) may very well do), but detail is more the forte(in general) of solid state so why not just try it to see how it works? As you mentioned, as ss and tubes units have evolved they are starting to converge somewhat, which is a good thing in my opinion because the newer formats, as they evolve and improve, are going to demand a more detailed but smooth and fully fleshed out presentation to reveal their full potential. In short, as recorded material improves(both in quality and amount of information stored) neutrality will become a more highly valued characteristic.
Anyway, I'd suggest finding a dealer who carries higher quality solid state products(sorry if the Atmasphere is ss--then this is redundant) and take home a demo unit or two. My first recommendation would be something like a Pass Labs unit as they are very neutral and revealing yet refined. If this goes too far in the other direction at least you have a solid reference and benchmark on the other side of the sonic spectrum from which to compare and proceed with other options. It doesn't cost anything(except gas and time) to demo, and I think this perspective would prove invaluable in helping you ultimately know for sure what your best option is. Best of luck.
Tim
Anyway, I'd suggest finding a dealer who carries higher quality solid state products(sorry if the Atmasphere is ss--then this is redundant) and take home a demo unit or two. My first recommendation would be something like a Pass Labs unit as they are very neutral and revealing yet refined. If this goes too far in the other direction at least you have a solid reference and benchmark on the other side of the sonic spectrum from which to compare and proceed with other options. It doesn't cost anything(except gas and time) to demo, and I think this perspective would prove invaluable in helping you ultimately know for sure what your best option is. Best of luck.
Tim