formZ 6.6, sometimes LightWave, sometimes Maya or Max. Depends on where the source model came from.
I try to avoid building my own models but dealing with TurboSquid stuff can be a real headache sometimes. It means always having to translate out of some format. If a model needs touch-up or alteration, I'll usually go into formZ for that, since that's the modeler I'm most familiar with and I like its precision. Like EIAS: same interface after all these years.
Sometimes after a reinstall, f/Z's icons revert back to their default 'color' mode, and I'm always completely lost. I can't use it unless the palettes are in the b+w mode from f/Z circa 2.0! Plus I've got an extensive batch of hotkeys defined, all loosely derived from either LightWave, Illustrator, or my own faulty logic, example, 'T' brings up "translate" (Lightwave), but "." brings up the Hand (me), and "-"/"=" increments in or out (Illustrator).
That sure makes for fun keyboard hunting in Maya.