Fallout 3 is the only game I managed to finish. I played FNV, Oblivion, Skyrim for hundreds of collective hours but just never managed to finish them.
I dropped F3 and FNV due to stuttering, but then found the ifpsclamp solution and was shocked at how much SMOOTHER that made both games (it's the ONLY solution that works however the game is unplayable if dropping below 60Hz on a 60FPS monitor... which I rarely did at max, 1080p settings using a GTX680/770 and some basic mods).
Oblivion and Skyrim were just so long life got in the way. I didn't plan to do every quest, but i wanted to do most of it.
Fallout 4?
Frankly, I won't play it. From the comments it feels like they've changed things too far away from the experience I liked.
I loved Morrowind despite the now very dated graphics and mechanics. Oblivion improved much but took some away. Skyrim did so even more.
The entire franchise just feels it gets more generic all the time. There are other titles I'd far rather play now.