My first thought upon logging onto TC5 are "What the hell is this..." On the new UI everything is big and colorful, and I feel like I'm playing Warcraft/a cartoon. But, I like to test things fully and give everything a chance before I jump to conclussions...
The UI is big and kind of silly looking, but it's nice once you get used to it. All your buffs show up under your name, and all the special abilities have awesome icons. The only thing I don't like is that the group window is like 5 pages long for 4 people, because of the buff UI thing. Also if a name is more than 2 lines long (like you have your profession under your name), it doesn't show up right and cuts some words in half. Names of things are in a new big, bold font, which is kind of weird, and they've got color coded icons next to them representing an enemies strength. Weird, but I can get used to it.
One of my first problems was with attacking. At first glance, it appears you have to hit either "Ranged Shot" or "Melee Hit" everytime you want to attack. These are the two basic attacks for Ranged and Melee. After I read a little bit of the FAQ, though (which is listed on the official forums), I found that if you ctrl + click an attack, it will keep repeating it, so you can set up an auto attack.
Some creatures don't fight back, which is...I don't know, realistic? Also the XP seems crappy, but at the same time it looks like I'm gaining it at a normal rate.
I like how damage works, because it's more simple. If you go into the combat window it looks something like this...
a lesser desert womp rat attacks Grask with Attack using a an unknown weapon and hits for 61 points (61 points kinetic damage). 61 possible points damage.
Grask attacks a lesser womp rat with Melee Hit using a an unknown weapon and hits for 24 points (24 kinetic damage). 24 possible points damage.
As you can see there's some trouble with names of attacks and weapons and stuff, but...whatever.
You heal at a fast speed, which makes downtime very short if you don't have Medic/Meditate or whatever.
Macros are a problem I think, because of this - in the skills page, they don't give you the /command for an ability, so I don't know what to type if I want to make a new macro. Not sure how this will work in the future, but just giving a heads up.
All the skill trees are different. Skills are in the same place, but when you get abilities is different. For instance, you get Pistol Whip at Pistols 1

.
So, my general impression after 10 min is this - goofy at first, I feel a little dirty, but after playing some I'm getting used to it, and I think after I get past the "I like my old SWG", I'll enjoy it. People complain about not being able to kill things on the forums, but they're crazy. I'm killing red cons solo no problem.
Uh...I'll post more as time goes on.