airport extreme tower vs pancake

So I'm in the market to replace my current router and have been waiting for the latest and greatest from Apple. Seeing that they just released the "tower" airport extreme, I was interested in getting it. One thing to note is I have Snow Leopard on my iMac so I can't set it up with the iMac apparently. I can use my iphone 5 though from what I understand. I just need to download the airport utility to my iphone 5.

So onto the question. I can't really find any factual comparison between the two models. I know the new one works in the AC range but I don't have any computers that would work with AC anyways so no big deal.

So really for me, the difference between the new model and the old one are about $20 difference. I can't set it up on my iMac. And the new model has beam forming or whatever it's called.

So is beam forming supposed to only benefit people using the AC wireless network or is it supposed to benefit all of the other wireless formats as well (A/B/G/N)?

Can someone point me to some factual information on beam forming as I'm not really seeing anything on these forums?

If you are not planning to change equipment or upgrade the OS anytime in the next couple-three years, then save $20 and get the older one, as you're not going to see one whit of difference.

The difference between the old one and the new one is that 802.11ac is about twice as fast, and the beamforming greatly increases the range. The beamforming may produce a noticeable effect on older equipment, but mostly you won't see the real benefits till you have 802.11ac stuff, which your next computer, iPhone etc will have.