Following Mercer was the first quest mod I downloaded. It's a small thing that ties in nicely with the Thieves Guild quest line. It's just one quest but it's one hell of a ride! Basically, when you break into Mercer's house you find a note in the basement (easy to find, it's right next to your Thieves Guild objective) that gives a hint on where Mercer has hidden everything he stole from the guild. I decided to follow this quest before finishing the vanilla quest line. Throughout the quest you get 5 clues at different locations, and you also have a secondary objective to collect plans for each of the Holds. First off is Irknthamz, a Dwemer ruin with a few surprises. After comes two caves (one with an entrance to Mercer's cabin) and a fort. Most of them are pretty small locations except for the Dwemer ruin in the beginning. Due to the content of the locations I may recommend completing the Thieves Guild quest line before completing the mod - but if you already know how the Thieves Guild quest line ends and have played it before it doesn't really matter. Though the fluidity of the mod may work better if you follow Mercer after the showdown at Irkngthand. Anyway - lots and lots and lots of riches, good fights, and it's also very lore friendly.
Falskaar was one quest mod that I really looked forward to. It's in the top 5 of Top Rated (All Time) in quest mods on Steam Workshop, and it really lived up to my expectations. Fully voice acted, with 26 new quests, lots of new items (loved the recipes, and there's a new house!), several new bard songs (loved them), two new spells, and a new shout. All in all the mod promises 20-30 hours of gameplay and it delivered. The voice acting is semi-professional, but there were a few characters I just couldn't stand listening to xD The mod also included cut-scenes (which is rare to non-existant in vanilla Skyrim), its own soundtrack, and the ending video made me think of Fallout 3.
Spoiler warning on the last video
Falskaar is an island outside of Skyrim that's basically its own country. It has three Holds: Amber Hold, Falskaar Hold, and the impassable Northern Hold. Basically the story tells of a group of Nords who came to Falskaar many generations ago and settled there. Hjalmar was the one of founded the settlements and declared the island their new land, but the land was harsh until Olav discovered a way to make it liveable. Because of this Olav's family, the Borvaldurs, became the ruling family of Falskaar, which rubbed Hjalmar's family, the Unnvaldrs, the wrong way. This supposed injustice has been the issue for several civil wars throughout the island's history, and now it's time again. Yngvarr Unnvaldr is looking to overthrow Agnar Borvaldur and claim the mythical Heart of the Gods, and the Traveler (that's you) must help stop him. Along the way you help several of the inhabitants of the island, and there's also a semi-Deadric quest line involving dream shards originating from Vaermina.
The most memorable moment for me was when I entered a cave while exploring, thinking it would just be an ordinary small cave. I have never been so mistaken in a game. The small cave turned into a huge Nordic tomb, which in turn morphed into a Dwemer ruin. When I emerged into an ice cave at the end of the Nordic tomb I thought I was done in there - then I noticed the Dwemer architecture sticking up in the ice. The ice tunnel led to a Nordic tomb front with Dwemer elements, where draugr and automatrons where fighting on the steps (that was cool). After having passed the draugr and automatrons the tomb completely turned into a Dwemer ruin. It felt like it went on forever, so when I got out of there - finally - I felt so relieved xD
The side quests included a lot of fast-travelling back and forth, but the main quest line gave me heartache several times. Emotional reactions is always a good review! Falskaar was amazing and I definitely recommend it to anyone who plays.