I like him.
He's annoying and ditzy at times, but he's a hero nonetheless. Yes, he's given Mary Sue storylines, but that's just the way things happen around him. He's cute; in the scruffy kid you want to hug way, not the attractive way.
I used to have a mini crush on him, until I became older than him. Now he seems so much more like a child. Sure, he should be stronger by now, as should Pikachu, but that, again, isn't his personality, but his story. As a character I actually really like him. If he was real, we'd probably be friends. Sure, he's friends with nearly everyone, but that just means he's friendly. He's hyper and exitable, loyal, brave and a good person. He respects living things and appreciates his friends and partners. He's got a good sense of justice, too.
As for his VA? Well, why should that make me not like a character? It doesn't affect his personality, after all. Dislike Sarah, not Ash. His dub voice makes no difference to the personality that the writers create for him.
He can be whiny, greedy and silly, yes. But what do you expect from a ten(ish) year old boy, especially one so surrounded by wonder and adventure?
As far as I'm concerned, Ash is a pretty cool character. I like him. =3
xX