If you are looking for a colorfull preamp with transformes (ISA, 1073 etc) then you might think this is not for you. BUT, this is an amazing, pristine, open sounding, ultra low noise preamp, with many many coloring options.
The two drive modes are very subtle but distinct, and the input impedance option gives you additional choices. There is really no microphone that you won't make the best of it with this preamp.
I alswo own an ISA TWO, and though I still track vocals most of the time through the focusrtie (I find myself to be a huuuge fan of lundahl transformers), everything else I track with the ssl now. Outstanging for drums, electric guitars, and acoustic instruments and top class at everything else.
Top class convertion to expand your I/O and/or use it for outboard gear, lot's of connectivity, and very very easy to operate.
I bought one a year ago, which sits on my studio and operates both as a preamp and as a converter for outboard units, and I bought a seccond one this month for a total of 16 SSL pure drive preamps to use on mobile recordings.
In my opinion, other than consoles, this is SSL's finest product yet.