Even though SSM has better writing and voice acting, and is overall a really great cartoon. Something about it just gives me the feeling that it's trying too hard. I don't know how else to say it, I especially thought Eddie Brock/Venom was kinda contrived and rushed.
Something about TAS still gives me a warm fuzzy I-Love-Being-A-Spidey-Fan kind of feeling. That I just don't get from SSM. Maybe it's cause I'm not a kid anymore, but I always feel like I know where SSM is going. I'm already sick of few episodes I've seen too often, where as I would watch any TAS episode no questions asked, any time I catch one.
Design wise TAS wins, the character designs were realistic and comic-bookish, while SSM is pretty cartoony. But the animation is smooth and fast paced so it makes up for the cartoonishness, that and not being constantly recycled like TAS. And like most people, I love that Spidey actual fights and punches in SSM. Give me another season or two and maybe my opinion will change but right now I'll have to declare TAS the better show.
However, this show DOES have the potential to eventually be the best Spidey show, it just isn't yet IMO. Now can we please get episode 16 on youtube?!