They're really low-impedence, which can be a nice feature when dealing with certain kinds of mics (ribbon, etc.). Lots of gain, but not the quietest thing out there. A little rolled off on the top and bottom giving it a bit of a midrangy quality. Pretty cool when driven to mild distortion; can get ugly fast if overdone, though. -20 db pad is extremely useful when mic'ing loud sources. Seems to kick out plenty of phantom power. Instrument input is pretty under-rated. Like it for direct bass.
Great, stupendous, awesome candidate for modding. Input transformer sounds kinda' cheap and dirty. Keep it in there if you like that sort of thing (might be cool for punk or low-fi stuff). Yank that sucker and throw something better in there if you want to clean things up. Throw some real tubes and maybe some Burr-browns in there, too, (it uses sort of a secondary opamp gain stage at the output) and you've got yourself a real mic pre.