Vespids are pretty good in the HoR format.
Sniper drones are ok (for marker lights and sniping) but they fall into the trap of there's something better.
Stealth Suits are ok (but something better is out there fun rules wouldn't recommend them outside of an OSC really)
Kroot are ok (for being cheap and bubble wrapping plus they can be good with sniper rounds but that's an upgrade where points could be spent elsewhere)
Hammerhead (without Longstrike are kind of lackluster the Riptide just does it better because of mobility).
Storm surge I couldn't tell you because I haven't used one.
Honestly the named characters are mediocre as well.
Farsight is good to pinpoint drop your units for devastating effect.
Shadowsun is hard to hit and lock down.
Honestly Ethereal or Fireblades are the best for infantry (mostly as the obligatory HQ in small point games but don't underestimate the Fireblades Volley fire ;D )
Finally the Forge world is good to have cool models (Crisis Suits) as for their flyers they are better than GWs but unfortunately not a lot of tournaments allow them :/
Oh and speaking of the flyers they are also lackluster. Maybe the Razorshark to drop plates on people and it's got the 360 degree turret so that's pretty sweet. Sun shark is kind of lame because of the possible "Gets hot" and not being able to make its bombing run.
But this is just from what I've seen. If someone has more experience please feel free to fill in or correct as needed.