I don’t much care for the TNG/DS9-style Klingons. They come off as half-retarded idiots (with a few exceptions, like Martok). That’s the fault of the TV show, but it’s been enough to put me off all the recent (i.e. from the TNG Kahless novel onward. Not exactly recent!) Klingon novels out there. I haven’t even tried them. I love the old stuff like The Final Reflection, and Ismael’s revelation about the Karsids actually made the TNG-style Klingons make sense a little (not to mention why their ships are so old, rusty and broken-down).
I don’t so much hate the TNG-style Klingons so much as ignore them. Should they disappear I might not even notice.
I’m all over the place with regards to the Romulans:
I dislike the Enterprise-relaunch Romulans (and the Romulan War arc, although I have yet to read Raptor’s Wing - it’s obviously not a priority for me). I hate that the great Rihannsu have been “de-made” as generic TNG/DS9-style one-dimensional villains. They leave me cold, as does the whole Enterprise relaunch (I’ll spare you the “it’s all wrong!” rant and rave). That corner of TrekLit can fall into a black hole as far as I’m concerned.
I hated the Phoenix Romulans too (not that there's any danger of them reappearing!). They can go.
I think the post-TNG Romulans (and Remans) are great (I thought Nemesis was really good, btw. You’re all wrong!). It’s weird reading the recent Romulan/Reman stuff, because it’s like a countdown (apologies) to their annihilation in Countdown/Star Trek XI. There may be Romulans still around afterward, but there won’t be a Romulan Empire - at least not one that’ll pose a threat to anyone (until more Romulan ships stumble across Countdown’s Vault! If it turned a mining ship into the Space Octopus, imagine what it’d do to a fully-armed Romulan Warbird! Galaxy = doomed)
I *really* hated (as in, was embarrassed to even look at) the TV Romulans in TNG and DS9, because of their dumb-beyond-belief shoulder pads and stupid bowl cuts. Whoever came up with the TNG Romulan look (and the entire TNG wardrobe, for that matter) should be shot. Later DS9 and Nemesis halfway fixed things, but the military still need haircuts en masse.
I thought Nero and his crew of psychotic space miners in STXI were brilliant (and they even had normal hair in Countdown!). I guess the Romulans have covered the whole spectrum for me over the years.