Full Disclosure: I'm a crazy person that still plays this game.
Edit: I guess the first expansion is called Knights of the Fallen Empire and the second expansion is called Knights of the Eternal Throne. Missed that.
With that out of the way I must say I really really enjoyed both of these expansions. The first expansion which covers content from levels 60-65 is definitely better than the 65-70 content that just came out his year. Sadly they are both called Knights of the Fallen Empire so there isn't a way to discern them unless you just call them Arcann's Story and Vaylin's Story.
I'll say gameplay wise nothing has changed but if you have been away for a while then they give players a "tutorial" to ease them back into whatever class they were playing. I found this to be mostly beneficial as at the later levels you can have a ton of skills that can be easily forgotten about if you aren't careful.
The one thing I did like about both expansions is that they try to mix up a lot of the mechanics to make fights seem a lot more epic. This is mostly seen with the "bosses" of both expansions but they are interspersed throughout the chapters of the story. A couple of these fights are subject to fail states if certain requirements aren't meant which made the mostly trivial fighting feel good again. The best part is that it really is a mostly single player MMO for those that just want to see the story.
On the bad side of things there is "Bioware Party" that you have to attend which is quite possibly the worst thing you have to play. Fortunately it doesn't last more than hour and didn't ruin any of my experience of what I considered a fun experience.
Be warned that a lot of your companions from the main story do not return. Also you can't mix and match companions during story elements of the game anymore. You are stuck with certain characters during the main story elements of the game. There are a couple of great new companions though that you get and one of those characters has quite possibly the
stupidest best moments in the expansion.
If you have any interest in it I recommend spending the 15 bucks to sub up for a month and blow through this. I'd say roughly the content is between 40-60 hours of gaming and while the combat can be quite a chore I never felt it got in the way once you understand the basics of the classes.