Well, I have to say - I did enjoy Primeape in the time we saw him, it had quite the funny personality and I loved it when it got angry. It was pretty funny seeing it take Ash's hat, seeing as it was actually the first Pokémon to do that. I was a little upset that Ash let it go away for training though, seeing as I thought they had developed quite a bond in that fighting tournament.
But overall, although I liked Primeape in the time we saw him - I think Pidgeot did more, and although like mentioned above me, didn't have much personality. It was a very loyal Pokémon and had a strong relationship with Ash. I also have to admit that time it saved the day in the episode "The Battle of the Badge Badge" when it defeated Jessie and James, even with those borrowed Pokémon, which certain was a highlight of it's time in the Anime. So yeah, my vote still goes to Pidgeot.