I'm also a 1st edition AD&D player and GM.
Ah to hit armor class 9 (THAC0), I actually miss that.
I'll add my two bits, and say that I find AD&D 1st/2nd editions to be more balanced than the newer versions (as you said, they're not worse or better, just different).
The old AD&D books have a mediaeval feel to them.
1st Ed AD&D felt like you were reading an occult manual rather than a Hollywood movie book.
It was crude, the artwork was raw and amateurish, and it didn't look like it was put out by a professional corporate marketing staff just trying to make a buck.
The terms were politically incorrect (meaning that they used the names of actual demons, angels, gods, etc), which added to its feel of being older and darker than it was intended to be.
I attribute that to Gary Gygax.
Gary Gygax put passion into those books, and when he left I think a lot of that passion left with him and D&D as a whole suffered because of it.
Take the concept of a clear line between what was considered good and evil in AD&D.
Player characters were allowed to play Paladins that had to be Lawful Good Humans (that should never have changed), while Dungeon Masters had at their disposal the Anti-Paladin character class (from Dragon issue number 39 page 8) to use as his antithesis.
I also liked being able to generate artifact weapons using the tables in the 1st ed. AD&D manual.
It made going through a lengthy campaign much more fun to acheive more than just some +2 sword.