I originally played through the game in its v1.3 state, and when I did, I found that the game was stable and bug free. I don't know how it improved after that, but I had no real complaints in v1.3.
I bought Phantom Liberty, but never actually got around to playing it.
I had already finished the main story, so I couldn't quite figure out how I wanted to get back into it again. Since Phantom Liberty was merged into the main story line, I'd either have to restart from the beginning, or start up my save game where I had finished it, and immediately get kicked into the phantom liberty missions, but with my way over-leveled character and weapons.
Neither of those options were desirable.
I did fire up Phantom Liberty to test it out, but I found that I could not play it. They changed some keyboard controls since the original game, making some controls hard-coded, meaning my keyboard setup no longer worked. I decided to quit and wait and try it again later. Maybe they'd fix the hard coded keyboard mappings in a patch later. No idea if they have yet. I haven't tested it.
When I fired up Phantom Liberty I also found that all of my save points from the "secret ending" of the original game were gone. I guess they wanted that gone?
I know I could remap the keys using the registry, but I never got around to it.
Even if they fix it - though - at this point - based on the aforementioned awkward merging of the expansion into the main story, I don't even know how I'd start playing it. Maybe I'll just wait until I forget most of the story, and do a from scratch re-play with Phantom Liberty installed.