The snakes did not look totally realistic to me, plus I was very well-lubricated with rum, so it was not the single most terrifying experience of my life, though I did spend a lot of time cowering on James' shoulder and screaming every time a snake lunged. Also, I was sitting between James and Elli and they kept poking me with the rubber snakes we brought and cackling evilly.
Earlier in the summer Poseidon pissed me off with its casual racism and sexism. Snakes on a Plane is the anti-Poseidon in that regard, and I really like the comparisons to '70s-era disaster movies, with a small group banding together to survive. And, of course, Samuel L. Jackson looked like he was having a motherfucking blast.
My verdict: Two snakes up!
(I'm still scared of snakes though.)