I'm just curious. If you are reading some (or all) the long fics, tell me which one you like the most and why?

No spoilers please.

I am going to skip over mine because that would seem a little narcissistic. I liked some parts of Past Sins, and thought that My Little Caboose was hilarious (except for the ending, which annoyed me for some reason). Austreoh was fantastic, and I recommend it if you've got the capacity to chug through the chapters.

End of Ponies is a class unto it's own, an excellent story which I fully recommend.

Right now I'm grinding through Eljunbyro, which is Austraeoh's sequel. So far it's okay, but it took a while for Austraeoh to pick up, so I'm hanging in there.

EDIT: Please note I modified the 'and why' part in the subject. Not really clever having it there if I said 'no spoilers'.

My Little Alicorn By InsertAuthorHere. To be honest, the first time i read Past Sins, i liked it, granted i was gullible being that it was probably the third fic i read, but when it was republished on Fim, i did a complete 180 after finishing it when i realized that Nyx was an incredibly well written mary sue, and also that the majority of the middle chapters dragged on about her crying over everything.

I have a three way tie for first place, that being (2/3 of them are series) The journey of graves by GentlemanJ, Aegis Shields Lunar Trilogy, and Past Sins by Pen Stroke.I found all three of these stories to have good character development, grammar and general enjoyability for the reader.

I'm torn between Diaries of a Madman and Man of War. Both stories are well written, have ridiculous long story lines (neither of which are complete yet), are completely original, and are more epic than a sonic rainboom.

Man of War: 682,649 words total
Diaries of a Madman: 977,401 words total
I haven't seen any other story that reaches the length of these two.

Well, I have many. Fallout Equestria takes the cake though. I mean, it has actual lol moments, and the consequences are proper, such as getting shot so much.
I also like Man of War and Diaries of a Madman. They are decent HIE fics.

My favorite long fic and overall favorite fic would have to be The Immortal Game. It is very action packed and entertaining the whole way through with a wonderful and complete overarching story and world. Also, almost every character and villain both canon and OC are exquisitely portrayed and logically coherent in both growth and actions throughout the story.
My second favorite would have to be Upheaval: Breaking Point just shy of 200,000 words. It also has a sequel or continuation story but the quality drops a bit for that one.
By no means have I read all of the long fics though and thus cannot give a true objective assessment as to which is the best.
Next I am considering reading BlackRoseRaven’s over 3,000,000 word series but have not decided if I am up to the task yet.

Fallout: Equestria
Need I say more?

How about an update?

My two favorite super long fics (that are also great HIE stories) are Diairies of a Madman (1,730,000 words+) and Your Human and You (488,000). Great epic storylines. Similar but still very different from each other and still ongoing. Other great long ones would include: Stardust (216,600 words ) which has Twilight on earth during alien invasion, Background Pony (432,377 words) the most amazing existential Lyra story, Life and Times of a Winning Pony (361,449 words) part of the Cloudkicker / Winning Universe. All are complete luckily and have some further additions out there.

Secret Life of Rarity is a great grimdark trilogy (4 parts actually with the spinoff The Word is Fear) that goes 380,000 combined. Past Sins was just ok. I can't really say it was anyway near as good as it was hyped to be. I guess having it be an early fimfic that gathered a lot of attention has helped it tremendously. Most of the other fimfics i also recommend fall a bit short of the 200,000 mark but are worth a read too and a few have sequel action.

Project Sunflower is pretty much my favorite fanfiction. It creates this amazing, believable universe that manages to captivate the imagination while still remaining optimistic. The consequences of the character's actions are fully explored and the story fully comes alive, both from the action stuff to the slice of life scenes that manage to add depth to the story.

Time for a necrobump.

The Hive series (starting with Of the Hive) is definitely near the top. It balances feels and action very nicely. It does have a nice concept, but I'm a sucker for any longfic involving changelings, which I doubt is rare.
The series lost me at the end of For the Hive. I was irrationally irked by that sequel hook, and just said fuckit. I'll be back though, since the same thing happen midway through me reading a different longfic, which I eventual finished (after other 'fuckit' moment of course)

Fallout: Equestria has been holding my attention lately, and surprisingly is actually good, something I don't expect from something that gets this much hype.

Jericho, is probably my all-time favorite, although it's possibly not as good as I think it is. It has quite a bit of FO:E influence, which I didn't pick up on having read this first. It's got the trite and true meandering plotline almost required for anyfic at 500K+ words and still not close to done.
Unfortunately, Jericho is currently on hiatus, as the author has taken some time from it to write an actual novel.

I'm also thinking about getting on BlackRoseHaven's wild ride. The only thing that stayed my hand is the romance tag, which I'm not big on.
(since I feel like plugging other authors as well, The Monster Below , The Chaotic Touch of Harmony, and Harmony Theory are other longfics on my to-read list)