Pre-patch:
Graphics issues - stutters, frame rate drops, occasional sticking. Many of these I noticed as being post-BS in F3. Large numbers of npc's and being inside buildings or enclosed areas compounded this.
Storyline anomalies - Not so much a glitch, but worth a mention. Many of these could be tidied up,
Random CTD's - Horrendous for me, requiring a game save after every purchase or significant event...I got to the point of saving every 10 to 15 minutes.
Losing Companions - Where's Rex now? Veronica, stop staring at the hoker....
Post-patch:
This is where things went down hill rapidly. Although I did notice some minor improvement in relation to overall stability, in that the random CTD's weren't so frequent, my graphics issues increased many fold, and the introduced issues were worse than pre-patch problems.
Monsters and NPC's became 'essential'. They would simply freeze in place, and at times magically teleport from one spot to another. Also, they would get stuck in rocks, etc, which meant that the companions would fight them continually, requiring me to go back to a previous save.
Lever-action firearm issue - Okay, I got to level 22 without being killed or seriously damaged. After this, I fell off the cliffs at Black Mountain twice, and got severely mauled by a rat. As well as Geckos, Ghouls and shot up by Veronica...I so love skating along the ground followed by a tap dance.
Hotkeys - First, the game would CTD when I tried to attach a weapon or apparel to a hotkey. Then it CTD when I selected the hotkey. Then it would CTD when I went to select an item in the pipboy that was attacked to a hotkey. This leads to the real game breaker:
Pipboy bug - Yes, folks, the game CTD whenever I now bring up the pipboy. End of game....
There are other problems that I haven't mentioned, as these have been largely overshadowed by the above. Unless a major fix comes out shortly, that's it for me. I'm going to give a restart a shot, but to be honest I'm not looking forward to it, this game in it's current state is simply too much hard work simply to play.
Although I got over 1600 hours of gametime up on F3, and although FNV really has some fine improvements over that game, and really has a lot of potential, I personally don't think that it has the goods in it's current condition, for me, to warrant the effort required to see it through to the end, even if I can get past the pipboy problem.
Good luck to those with similar issues who do persist with it.