I tend to find HRs to be the quietest genre... they're not fast enough to be SHR populated, but they're too fast for the LR/MR crowd's tastes.
But no less, they tend to have the SHR's focal points; the end goal is WoE, if not PVP and as was mentioned earlier, drama. Drama, drama, drama. Many players just sort of fashion a second life out of the server (as harsh and generalizing as that sounds) and so you typically wind up with a server where PVP is full of smack-talk and ostensibly aggressive behavior (swearing, taunting via PM, mouthing off about you in town, etc. etc.) and the prominent classes are Monk and Assassin variants. I've been on a few good servers here and there, but if you're playing RO for anything other than to waltz through PVP with a Sin-X/Champ, S/HRs are probably not your cup of tea and will most likely be full not only of people who only speak Tagalog, but will have @afk/@logout'd populations whose small active portion sit in PVP and talk with their upper echelon of guildies, taking a tea-break to mass-gank anyone who stumbles in unknowingly, or they all sit in the main town bantering idly until WoE comes, whereupon they all basically sit and stalemate at their castles, sending out scouts to each opposing guild's area, and swatting what scouts come through their doors.
(Note, of course, this is all generalization. There may be a diamond in the rough somewhere if you search.)