More SH4 for me than SH3, though I've got them both installed. SH3 looks so ugly nowadays that I usually need a really good reason to fire it up(like getting fed up with the outrageous tonnage in the u-boat add-on in its stock form, new GWX version getting released, etc)
Then again age doesn't really count much if there's no good alternative, Falcon 4 being one good example. Even though the original game was released back in 1998, people still play Falcon 4 AF(among other Falcon "flavors") which is really a heavily modded/updated version of the original.