I have tried several compilations and am an enthusiastic, if generally ignorant, early addon adopter
Even so, Mazzle UI has introduced me to so many really great addons that even look good, and it's been so excellent to have all that functionality without the clutter I had made for myself. That was the real reason I was looking for a UI - to try to get rid of all the junk I had on the screen but still have all that info and doodads.
Baggins has got to be the best bag mod ever - and I have tried several, ever since finding AllinOneInventory. I use most of the Fu stuff, which was new to me - GuildFu is extremely useful, as we have a very alt-friendly guild, and I can now see our guild notes right away and easily tell who is who.
The chat setup has helped me a great deal, and I love the way consumables automatically appear, allowing a choice of what to drink/eat/use when there are more than one per category.
Free Refills has, I'm quite sure, led to a loss of brain cells, since I never ever worry about being out of reagents and now amaze my friends by always having extra
I used to use the ct_mailmod function that allowed several items in boxes that then all got mailed out. The one with Mazzle is so much faster, though, just by alt clicking - I was surprised.
And it goes on. I like everything so far - oh, I have found Bongos and also the categorizing of the Blizz keybindings *enormously* helpful - Bongos is the first keybindings addon that I have been able to use easily and quickly, and it has made me a better player - which is one of the goals of a UI, right?
Finally, the whole philosophy of MazzleUI, the humor and graphics, your personality expressed through the UI and instructions/FAQs, etc., really makes it a lot of fun to use (also one of the goals of a UI?) - and the 3D models across the bottom are now something I "need" to have WoW seem like the same game anymore. Thanks!