Most servers have one kind of annoying flaw, but it isn't really their fault. That is, multiboxing. That is playing 6 characters with 1 real person and eliminating the need to group.
But for EQ.. You have Project EQ, which is probably the best emulated "live-like" server around. They are up to the LDon Expansion, with minor touching on other expansions and you'll find things missing here or there, but they really tend to press the standards on itemization, contents, quests, etc. They're open source, so other servers can typically base their work around it, but not saying they aren't putting in their own work too!
Then you have Project 1999, which is an original-like version of EQ, it is aiming to recreate the old feel of 1999 EQ. This one is pretty hardcore, with an IP limit of 1 (unless you can convince them you have family at the place and get an IP release, but even then I think only 2 per IP). This means you can find groups, but on the same breathe, P1999 is very slow EXP. They have penalties, hell levels, and many things that were done away with in the evolution of EQ.
You also have quite a few custom form servers, catered for the lower community you may find, such as StormHaven, The Hidden Forest, Gnomish Proving Grounds, etc etc, these ones take the original idea of EQ and twist it to be a more customized experience.
Storm Haven's maker (trevius) did a lot of the contributions to get the SoF client going, and they have worked on custom SoF-zones, so if you want to play Drakkin their support is pretty good for them. They also keep putting in interesting custom quests of randomness, and in general I enjoy their style of customization.
Some servers specialize in PVP, others may specialize in other ways, but generally speaking most fit into the above categories.
Personal opinion: I tend to enjoy THF due to it's smaller niche community, and close GM community support. When I started THF I immediately found people to become friends, people were overall nice, and it was pretty easy to get up to a point you could contribute in a guild with time invested.
Project 1999 is a "full time commitment". PEQ I can't seem to find myself playing long enough to get anywhere, and I've played around on nearly every server at least once on the preferred list, and each one has their share of interesting features.
In other words, play around, talk to the poeple there, see what you think of their ideas.
All EQEMU servers tend to have bugs and some times band aids are applied differnetly to the bugs.