Quartz is currently working fine for me without having to turn off any features. The only problems I'm having are with configuration. I'm assuming this is because 3.0 changes the way AddOn settings are stored, apparently "some" settings are/can now reside server side.
For those that are interested, there's an informative post on the US WotLK Beta forum (UI + Macro section) that lists all working mods. Link: WoW Forums -> Functional Add-ons
Tip: If you find that an AddOn is working (as in it displays or functions) but you can't configure it to your needs try this:
Load the AddOn in the live release of WoW
Configure it to your needs
Close/logout of wow to commit the changes
Find the SavedVariable file associated with the addon and open in WordPad
Do a find and replace with "Your Realm Name" to change to "You Beta Realm Name"
Do a find and replace with "Your Live Character Name" to "Your Beta Character Name"
Copy the Lua file into the WotLK equivalent folder (replace if neccessary)
This is what I did with PitBull and Quartz as the Ace2 config window kept throwing errors.
The list on the US forum seems to have a mistake or two. Last night I installed MobHealth and it worked fine with IceHUD. I used JWoWUpdater to install them and haven't noticed a problem yet. Also, you can config IceHUD in-game without problems (just type /icehud to bring up the config screen).
[10:05:49] <Nat> how do u know if a unicorn is a virgin?
Power Auras Classic seems to work fine in the beta. Which is particularly nice for Blood DK's thanks to all the proc-based buffs, particularly if you want a more obvious visual cue for something like Death Trance or maybe even Scent of Blood.
I'm using the latest ItemRack and OmniCC on beta...both seem to be working but the "Options" folder for both are red on the list, no idea why. I guess I should check their TOC to see if its at 3xxx.
Chatter is working decent but there are issues with it: it doesn't allow you to access any options in the chat tabs once installed. The default UI has a variety of bugs right now as well (ie ESC key not closing most windows, significant FPS drop with dynamic shadows turned on and opening UI panels)
MobSpells is a very nice have against new creatures.
The first batch of author names (from our author beta key give-away) is being sent in to Blizzard today, so *hopefully* they should start seeing their keys within the week (no promises from me though).
Once they are in and can start working on their mods, expect to see our WotLK Beta download category to start getting busy. So, what can you do to help? Check out mods in that category, see if they work properly or not. If they don't, give the authors as many details as you can as to what isn't working, what errors you get, etc, either as comments on the download page of that mod, or in the special forum we made for them.