The setting of Fallout 3 is definitely not something that is to my liking -- a post-apocalypse nuclear wasteland does not sound particularly compelling. I have seen the game be praised on multiple occassions, however, and I ended up buying it myself -- about a year ago, it would seem. My previous and short-lived experience with the series was Fallout 2 where I got far enough to kill some scorpions (I think) before quiting because the game was not like Infinity Engine games I so love.
When there was no task involved, exploring the wasteland and its locations was awfully dull. I think Bethesda learned something between Fallout 3 and Skyrim, because in the latter wandering around was much more interesting. I realized this after I had done two DLCs and thinking how boring the additional content for FO3 was but then coming to the conclusion it was the whole game that was lacking.
Environments filled with ruins were dull to watch and even the combat felt awkward. I tried to play the game as a shooter but not being able to aim down sights and the reticle being what it is made it impossible. And using the V.A.T.S got repetitive, no small thanks to the slow motion death animation after every single kill. Sniping with the scoped guns was probably the most fun I got out of FO3.
Degrading equipment and weapons may have thematically fit the game but I found it an incredibly irritating mechanic. Towards the end, when I was done most of the stuff, I started using the player.srm console command as I had gotten really tired of trying to find similar weapons and armor to fix my stuff. And there even are many unique pieces that seemed to be only repairable at a store, like the gauss rifle and the wintery power armor.
I found Fallout 3 to be often rather challenging. Early on, the radscorpions gave me trouble, and in the late the game the super mutant overlords and albino scorpions seemed to be able to take unwarranted amount of punishment. Midgame was fortunately fairly smooth. I had heard deathclaws being dangerous but they seemed to die without too much effort.
I played Fallout 3 on my old machine as I already had Nexus Mod Manager installed on it from playing Skyrim and the game does not exactly have the highest system requirements either. Although I did still set the options to pretty low (including lower resolution) to make sure I was playing at 60 fps all the time. I have gotten so used to it now. But the computer probably could have handled more.
Most of the mods I installed were for stability and bug fixes -- though the game still crashed occasionally. One mod, Fellout, supposedly removes some green fog from the game but it also makes the nights extremely dark. The modder's justification for it is real-life nights in the wilderness being so. Be as it may, I installed another mod that made nights brighter again. Unfortunately it stopped working at some point and I avoided nights for the rest of the game. I guess I should have uninstalled Fellout, to think of it.
Even though I did not greatly enjoy Fallout 3, I tried to explore all of it so that I never have to return to it. (I missed quite a few of those bobbleheads -- a loot highlight mod would have been great again.) Fallout 4 will probably have to wait for a good sale and for when I am really out of games. Fallout: New Vegas I will play, however. I bought it together with FO3 and actually am already four hours in it. It seems a lot better game.