I know many people in the electronica/hip hop scene using T-Racks.
If you're after "warmth", aka distortion, they may be just what you need. As dynamic processors, I do find them pretty average however. I'll sound like an heretic, but I think the old golden compressor is still the best compressor IK has to offer. Yes, better than the Black and White ones. But that's just me.
So it's not so much a matter of genre - anything that you think could benefit from a bit of
warmth if it's something you find desirable, T-Racks will cover.
As for the limiters, I've heard good things about them - one of my pal doing techno swears by the Limiter, even if he owns all the Waves and UAD stuff - but I haven't really put them to the test, and I don't do mastering.
If I had less than $75 to spend on a good compressor and EQ, I'd grab Waves Musician Bundle 2 while it's on sale - which includes Renaissance Comp and EQ - or Focusrite's Midnight Bundle.
As for Linear EQs, I have one that's even more flexible bundled w/ my DAW software, so I have no use for T-Racks EQs (though the Pultec is nice.)
Not that T-Racks is bad, and at this price it's quite a bargain. But to me, it's more geared toward giving people looking for that elusive "glue" what they want. If you really want to shape your mix - not just glue it - I think there are better tools - including some that come bundled w/ Sonar.
EDIT - Again, I'm talking about mixing, not mastering.