Worst and best planet?

Best: Voss
Worst: Taris (Republic)

Worst: Balmorra. It just takes forever and looks a lot like several other planets.
Best: Quesh. It has the right lenght, its dragged out too much on most planets, causing the game to lose focus.

Overall I'd say Bioware ought to add some more varied level design since many planets look very much the same regarding structures. Especially Tatooine looks nothing like Tatooine in the cities and villages. The structures seem too advanced. At least they should redo the space port into the style we saw in the movies and in KOTOR. Seems to be plenty of reference material for it.

Worst: Alderaan, because it's the last planet of chapter 1, and you want to speed up and finish it, but you ended up with a huge open world planet, which takes hours to finish.

Best: Kaon, filled with zombies, what's not to like?

I like the more open planets like Alderaan, Tattooine, Hoth and to some extend Voss and Dromund Kaas best.
I don't really like tunnel planets like Belsavis, Belsavis or Corellia but i do think that Coruscant and Nar Shadda are pretty cool because they feel alive the most.

For upcomming planets i do hope they can manage to create a planet that feels open and still feels alive.

I agree on both points. Other than Belsavis having a great graphic toll that nearly prohibits my usual computer from playing on it, the planet is large, diverse, and quite interesting. I liked the world story as well as the aesthetics. The ending of the Trooper arc was also very sweet.

As for Quesh, I'd also like to have seen it scrapped. I had high hopes for Quesh pre-launch since it sounded so unique and it was a planet I'd never heard of before. However, it turned out to be such a small, useless planet with only one class mission per class and about 6 total missions altogether. A lot more could've been done with it, which I find disappointing.

My personal favourite is Hoth and my least favourite is either Coruscant or Balmorra. Both of them make me want to just stop playing that character once I get to either planet. Balmorra is so close to Hoth, so that's what keeps me going.

The copy and pasted spaceports really take away from any originality or personality that any of the planets could've had. It's a shame really.

Worst: Belsavis, jep me too. Too much chaos and difficulty traveling. If you like that sort of stuff I can imagine it being your favorite planet...but not for me.

Best: Nar Shaddaa and Tatooine. Both feel 'real' to me and are totally different which is nice.

If you asked me a week ago: Nar shadaa.
But now that im choking my way through it at level 33, it has to be Taris (empire). I know i hated this place as republic, but more for the fact it just never ended. But on empire its a whole nother level.

I look forward to seeing belsavis though. If tanaris almost had me quitting the game again through mnd numbing grindcore, then im sure belsavis will send me to another mythos.

Clearly the worst is Balmorra (Republic)... such a boring planet...
The best is imho Voss. Very fun planet.

Dromund Kass is a also horrible, too small, with corridors, abd if you fall from top to bottom, you have to travel across all tombs as a new incomer... what a joy to kill again all trashes... A way to go from bottom to up would be a great improve.

Best: Tatooine, Tython
I like Tatooine because it's a planet that is not so corridor-like as some of the other planets and feels more of an actual world because of it.
Tython is a corridor, but it's really well done with a lot of attention to detail.

Worst: Taris (Republic), Corellia, Belsavis (Republic)
Taris I dislike because it drags on far too long without a speeder and feels too confined.
Corellia to me does nor properly convey the sense of an all-out war, but more like the riot police rounding up soccer hooligans after a match. Balmorra does that a lot better.
Belsavis is a great planet for the first part, and I love the scenery, but the latter part is just a drag with tunnels that just keeps on going. A shame, because it's definately is a world that stands out.

The main issue I have with a lot of planets is that despite their size they tend to be broken up into small, closed off areas with tons of mobs thrown in your way that only seem to exist to slow you down. Even planets like Tatooine and Hoth, which should be barren because of their harsh climates are bristling with activity. I don't mind the odd patrol, but for a Star Wars game it feels weird having to act like a mass murderer every time I simply want to go from point A to point B.
I think that opening up the planets and removing mobs from the travel routes and concentrating them more in pockets would make the whole experience a lot more enjoyable.