The CAT preamps are very, very good tube units, and I believe that the Legend is currently the best iteration (I owned a Mk. III many years ago).
Sound quality aside, downsides are excessively high output, which reduces the range on the volume control with sensitive amps (e.g., 9 O'Clock position is already loud and 11 O'Clock is super loud), no remote, and a hard-wired power supply connected by a stiff, thick umbilical cord that is unwieldy.
Th phono stage works with MC's down to 0.4 mv. output without problem - MC's with lower outputs require especially low-noise tubes.
Only the very top preamps are better.
Sound quality aside, downsides are excessively high output, which reduces the range on the volume control with sensitive amps (e.g., 9 O'Clock position is already loud and 11 O'Clock is super loud), no remote, and a hard-wired power supply connected by a stiff, thick umbilical cord that is unwieldy.
Th phono stage works with MC's down to 0.4 mv. output without problem - MC's with lower outputs require especially low-noise tubes.
Only the very top preamps are better.