I've completed the game. Done most of the secondary quests too.
*** Warning: spoilers ahead ! ***I've finished with the legion, but done all the quests for the others too up to the critical point.
Spoiler:
All 3 endings are somewhat dark. The Legion are slavers, the NCR are oppressors that try to get more and more land and the robots are terminating what does not comply with their system of control.
Too bad I had to destroy the BoS main bunker. Other then that, the Legion quest line is good enough.
This is somewhat a limited thinking from the developers: since BoS and NCR were in conflict, I see no reason to eliminate BoS if a non-NCR quest line is followed.
Regarding weapons, the most useful one is by far the Gauss Gun. I also used the sniper a lot and the Laser RCW. The Tesla only when very high damage was required.
I didn't find any laser minigun (do tell me if there is somewhere).
Didn't use VATS more then 10 times in the whole game, since my rifle accuracy is better then VATSes ideal maximum of 95%.
The most useful perk is the one showing you all locations, but my favorite still remains Bloody Mess.
The most useful in combat is the one that makes the things you kill with energy weapons explode.
I still have a few locations to go to, but they're kind of irrelevant (like farms).
Overall, the game is good, but the main quest line is kind of weak. Legion is not by far comparable to the Enclave and BoS are next to a relic. NCR is the only really powerful force in the game, so that's one of the reasons I decided to go against them. Also, the Supermutants are just remnants of the old tough ones.
There are no special encounters...unfortunately.
That's it half-briefly.
If you need any help with quests, locations, bugs or anything else, drop a few lines here.