For Cataclysm I'm playing on a fairly new Mac Pro Laptop and have elected to just use the default UI. I have no pleasure of having again to deal with using the world of addons and more addons installed for WoW and more especially to download them to my new PC for all the trouble they can be. So its also a bit just getting used to using the default UI playing as well.
I'm just barely at around 58K HP so far and slowly have replaced about 4 or 5 pieces of gear. Its quite shocking to see other players in zone with over 100K HP and having seem others with over 150K HP already in city. With my old WotLK epic progression gear it don't seem to last all that long into the next expansion. Makes me wonder somewhere deep down in my mind about the rat race at the level cap for gear progression and the effort and headache that can be. However I'm also glad as well to get rid of the gear as I pick up better Cataclysm pieces leveling up to 85. At least the answer that I was looking for to clean out my personal bank of the old epic gear and gears is clear that I can junk vendor it all.
Since I was questing in Vashj'ir I had flew to Undercity to bank/AH some stuff and out of curiosity I picked up a quest that ask me to head to Mount Hyjal by way of Orgrimmar to Moonglade. Just did the initial quests to get to the zone, picked up the new Flight Path's and complete the first real quest. Zoning into Mount Hyjal for the first time was very cool seeing Deathwing which was cool. Place looks really pretty, reminds me a bit of Night Elfs land so far.
Thought about questing there a bit in Mount Hyjal. However already had more time already invested and having done most of all the initial zone quests and didn't feel like starting over. So headed back to Vashj'ir zone to progress on questing there. I get the feel that Mount Hyjal may be more about Elementals invasion and Vashj'ir about the Nagas.
One the more difficult thing so far is figuring out a combat rotation on spells once combat starts that seem to work smoothly without clashing global cooldowns compared to how i remembered It used to be in WotLK with a smooth rotation. And so far I haven't figured out one as yet that works well. Often seem more like just button mashing most the time when cooldowns are up for the spells I primarily want to hit. At most I can figure having maximizing having more Holy Power charges seems good to be able to slam big with Shield of the Righteous, hitting harder with Inquisition with more charges or a good self heal with Word of Glory. Still getting used to using that too.
I guess it could be easier to get the answer with more knowledgeable understanding behind actual mechanic of talents and skills if I dropped by the Maintankadin forums and read through the a Cataclysm tankadin threads and figure things out.