Well then...just finished playing through every faction in FO4. This has been interesting...if you want to see my thoughts (from the moment you change allegiances) I'll post them w/spoiler tags
The Institute:
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Decent. Mass Fusion is boring. Make sure to kill the Assaultrons and Sentry Bots for some sweet junk and a few fusion cores. When it comes time to hack Liberty Prime, just use synth grenades at each stairwell and take a nap. Elder Maxson flew away in a Vertibird (despite me shooting it down) so I had zero time to find his body and get Final Judgement 
This ending felt the most canon to me. It was kind of nice having a good conversation with Father/Shaun in his final moments, and learning that he reprogrammed the Synth to be him at 10yrs of age. I know, Sole Survivor thinks its been 10 years since the war, but why not just make a baby synth and go back to the way things were pre-war with Shaun as a baby?
And why did they really make Father say "I'd like to go to sleep now." ? ? ? Seriously? Weak sauce.
Anyways, I didn't encounter many bugs during the final questline (Mass Fusion and beyond). it was AFTER. Dear god...why...
First, the battle music would not stop playing after I said goodbye to Shaun. Even fast travelling did not change the music. I had to turn the radio off and on again to fix this issue.
Secondly, there is a bug (according to the Wikia site a known one) where you cannot give Shaun the first junk item he asks for. This renders him unable to build the Wazer Wifle...great...good thing I found the prototype already.
This ending feels really weak. You're director of the Institute, and you get to do nothing but radiant quests AKA do other people's jobs. There's nothing to stand for it, and everyone else is gone. Well...except the farmers I guess. And a more paranoid Diamond City... I don't recommend this ending. 5/10
Brotherhood of Steel
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This ending was admittedly the most badass of them all. But there seems to be a major glitch (at least for me), when trying to direct Liberty Prime to attack the Institute. Prime just kept walking into the BOS barrier at the airport no matter where I went. I had to fast travel (I chose Prydwen) and just jumped off the side in my power armor. It was still doing it...then somehow the game fixed it and I continued the quest as normal. I think this was the only major hiccup in the ending quest line.
Since you can't kill Elder Maxon you can't get Final Judgement...but I think you unlock T60-MK VI armor, and that sweet jetpack...I like to think it functions as Jet and drains all of your AP and fusion cores. Better have the Action Boy perk leveled up...I only like the jetpack using God Mode and collision disabled...fly anywhere for DAYS like a jetpack from a Sci-Fi movie.
Besides Minutemen I think this faction offers the best post-game quests. Dead drops are annoying, but then again so are finding technical documents since Proctor Quinlan will not shut up about them...Decent ending, but not my favorite. 7/10
Railroad
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To the best of my knowledge this was the only quest line that didn't have any major bugs in it. It was a little annoying to have to do Mass Fusion again, but whatever. There IS a bug with this actual quest, at the very end if you do not exit the building and instead ride the elevator up to the executive suite you will not only glitch out but the game will not recognize you've left the building no matter where you are. You also can't move, doing so results in instant death unless you have power armor due to the height you fall from.
Anyways, after doing 2 playthroughs everything was relatively smooth. It's all just kind of the same. However actually being on the Prydwen and having Tinker Tom fly the Vertibird is really awesome. To counter the BOS where you kill the Railroad (or maybe it's the Institute quest line), all of the carnage is amazing. THAT, and if you are resourceful like me, raiding the armory is AWESOME. Mini Nukes, X01 helmet...Fat Man...so many goods.
The only thing I didn't like was spawning to the Command Deck and having Elder Maxson and a Knight just light me up immediately. Stimpack at the ready, Explosive Minigun to Knight and Maxson, done in 5 seconds. And FINAL JUDGEMENT GET.
My personal favorite as directly attacking the Institute and BOS was great. I got the most/best weapons with this playthrough so I will continue from this faction. 8.5/10
Minutemen
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If you like LOL EASY gameplay this is for you...seriously. Way too easy. All you have to do is defend the castle, and you can just wall everything up using foundation flooring. Have about 20+ power at your disposal, hook up 2-3 or more missile turrets, and this is cake. You can even be in workshop mode while the battle is happening. I mean come on...
I was not expecting teleportation INSIDE the walls. But whatever. A few machine gun turrets fixed that.
The BOS attack was even easier. Just worried about my missile turrets. However, there was a Vertibird that was stuck at about 1% damage for 10 minutes, even after 100% Defend the Castle (talk to preston/ronnie) was reached. Just a constant stream of laser musket rifle sounds...it would not go away. I went through the Castle Tunnels and back to fix this. Vertibird gone. WHAT?
Building Artillery to blow up the Prydwen...yawn. Though, watching the Prydwen blow up from the Castle in the morning fog was seriously cool. Then that's the game...
Attack on the Institute plays the same as BOS and Railroad. By now...yawn.
Decent playthrough but this quest line does not make it worth betraying every other faction (you do fail Railroad and all future quests as they give up). 6/10.
TLDR: I don't know why content was so reused for each faction. I guess the goals are similar, but often times it was just doing the same thing over and over. So much for unique playthroughs...I am glad I did it this way. That and these game breaking quest bugs are just ridiculous. As much as I love this game if it wins a GOTY I will be a bit upset. There are more deserving games out there, like MGSV, I'd even say Undertale if you've ever played it. But anyways. As to what's next, GOD MODE FOREVER, MODZ FOREVER.
