Alright, suppose i'll share my thoughts about Leviathan now when it's cool with spoilers.
I had little.. actually no expectations on the DLC. I went in figuring it was crap and that i wouldn't enjoy it at all. I'm very cynical when it comes to Bioware nowdays but for once i didn't come out on the otherside annoyed. Bioware did suprise me with actually making a good DLC that i had fun playing. Naturally if it had been part of the game from release my annoyance towards the starbrat might've been less vicious.
Leviathan was the DLC i needed to not uninstall my copies of the games just yet.
It started of just perfect for me. Almost getting shot in the beginning by the assistant. I absolutely loved the investigation part where some information were relevant while other looked like it was useful but in the end it wasn't. Bioware did a good job there and EDI was quite cool.

"TAAACKLE"
One word about the mining base, creeeeeeepy! But i really enjoyed the part. I was constantly looking around every corner for a Reaper or two. Something was so very wrong here and with all the miners making a camp in the uncanny valley it just made it so tense. I enjoyed this part in Overlord and here i enjoyed it just as much. Having the squadmembers talking probably made me not go insane in there.

"Something is off here"
Namakli was the least awesome of all the planets but it was fun nonetheless, i enjoyed the rush of having to reach her fast. It was quite fun to dodge all the Ravagers while at the same time knocking out some banshees.
Rescuing Ann was a must and having a must hanging over me was great for once

Cracking bad news is something Sarah is used to. It's nothing special until it's telling someone that their father is murdered. Family is sacred to Sarah and it always pains here to tell someone they lost a member of their family.
Also finally Desponia, bad things first. I miss having the armor looking soaking wet. Bad Bioware! Now onto the other parts. All the datapads talking about the things that happened there was awesome to read. Cortez kicked ass here as on any other planet. That man is super! This planet felt a bit too short but it had it's jewels aswell. Having to fight on an area that awkward was fun and having to gather the battery to the Triton was horribly easy but fun nonetheless. Diving into the sea was quite cool

During the descent i had
"Under the Sea" in my head all the time.
Being on the ocean floor was an interesting experience and it would've been great if it was longer than just the tiny walk it was. Meeting Leviathan and his crew was both cool and hilarious. I had issues getting past the giant cuttlefish part but Leviathan himself was a great cuttlefish. His explanation of what happened made me both facepalm and cackle so all in all. Cuttlefishes shouldn't do science.

One of the best highlights of the entire DLC and..

Having Sarah get rescued by Kaidan in a situation like that was just perfect, it was long overdue to. Eden Prime, Virmire, Horizon, Mars, Earth.. she has saved his ass so many times that it was time for him to be able to return the favor. I really liked that he got saved Sarah, probably what i enjoyed the most of this DLC, having the LI saving Shepard.
So all in all i'm trying to be as objective as possible and push my dislike of everything ME3 related aside and giving the DLC a fair opinion. I'm considering it as good as LotSB in many areas. LotSB was great and i'm liking Leviathan quite a bit so it's either as good or not far behind at all. Well done Bioware