I've been a regular user of Healbot for most of my WoW time for some specific reasons. I've tried Grid+Clique, Xperl+Clique and Xperl+mouseover macros but eventually wound up with Healbot because as a resto shaman I need to see who's got my earth shield and how many charges it had on it. Others would show the shield but not the charges and would therefore hamper my effectiveness (Oh look, the shield only has two charges left, I have a free GDC right now and a bunch of AoE damage is coming. Maybe I should refresh it!). Healbot did everything else I needed sufficiently. All the raidframe addons these days are fine, it's just a matter of personal taste.
My UI generally looked something like this with Healbot:

Then I leveled my druid and started healing with her. A druid has a lot more icons to track thanks to all the HoTs. Healbot shows them but just kinda plops them on the bar in the order they were cast, no particular organization. It worked but it was messy. I tried VuhDo and liked it for the druid but couldn't figure out how to get it to show my shaman's shield charges so went back to Healbot. Recently I read Vuhdo could do it, just took some configuring so I decided to give it another shot. I'm very glad I did.
The shaman's UI with Vuhdo:

Looks pretty much the same right? Of course it does, I set it up that way! There are a few differences though and they are important ones. Vuhdo lets me choose exactly where each buff icon will be placed so it is always in the same place. What's more, Vuhdo tracks buffs that Healbot did not. Ancestral Healing is a very important buff that I place on somebody when I crit heal them, it is important to keep it rolling on the tanks as much as possible since reduces all incoming damage by 10%. I can crit my Lesser Healing Wave *almost* at will thanks to Tidal Waves but before it was 'cast and hope it lands', couldn't be absolutely positive. I set Vuhdo to show Ancestral Healing as an icon in the middle of the health bar so now I can track exactly who has it and how long it will last. I also decided to track Earthliving Weapon which is something I've never done before and it's been interesting.
Some other shots from last night.


I wanted to get some pictures of in combat stuff to show incoming heals, range, debuffs, threat, ect but was to busy

You get the idea though. You can tell it how to show debuffs, it can look like anything you want it to (squares, show class color on the bar), ect. The author built it to be just as customizable as Grid without all the plug-ins, everything comes in one package.
Here's a shot I took of the druid in a party earlier today. Gotta talk about her since she triggered all of this.

I put Rejuvenation is the upper left hand corner, Regrowth is bottom left. Wild Growth is upper right, Lifebloom is bottom right (and it will track the stacks of course). Abolish Poison goes in the middle. One of the cool things is that bright pink dot. Kind of hard to miss isn't it? That means the target is Swiftmendable. A target will get the Swiftmend dot if it has any applicable HoT on it from any druid, not just yours. So another Druid could have Rejuv on the target and the dot will show so you know you can Swiftmend as needed. I really like that.
Quick word from the paladin side, like the others you can tell it to show what you want where you want. Beacon, SS, FoL hot, ect all work fine.
I like to keep all my targets together but if you like to separate out your frames (tanks, focus targets, ect) Vuhdo does that. It was fine on the memory usage, stayed under 2MB all night. You can have the menu drop down from a minimap icon or on Fubar (I have the Fubar option). It works with mouse clicks or mouseover macros, whichever you prefer. You can bind other macros (like on use trinkets) as well. You can see it shows nice detailed tooltips, it will also show conditions like afk or ghost.
Overall it looks like I'm going to stick with Vuhdo. It's like Healbot with a bit more detail or a slightly more user friendly Grid. I like that it comes in one package, doesn't need plug-ins. It's well known that Blizz is working on the default UI, I hope they do a job as nice as this. Overall Vuhdo gets a big thumbs up from me (Shaman and Druidside).
"Let's face it: armed combat beats unarmed combat any day of the week." Tom Clancy