Lately there has been talk of a new threat meter addon that's based on the Ace2 framework called Omen. It was very well recieved on the Elitist Jerks forums, so I decided to take a look at it for myself. Now, I am a long-time KTM user, and I can say that I've been pretty satisfied with it over the years, but this new meter completely blew me away. Sleek and stylish, Omen is quickly catching up to KTM in terms of popularity. It's packed full of features, such as multi-target threat, extensive coverage on threat generated by the abilities of all nine classes, synchronization with players using KTM, and it looks cool to boot. The author of the addon, Antiarc, devotes huge amounts of time to its development, and updates it with new features and fixes nearly every day.
However, Omen is still in the development stage. It has its minor quirks and glitches, but with time they will be worked out. So, next time you're browsing the Ace2 site, try downloading Omen and testing it out. I did, and I must say I'll never go back to KTM.
Omen can be found on the Ace2 files page at http://files.wowace.com.