I don't have an E1 and can't put up pics easily anyway, but from what I understand the E1 has a considerably brighter and narrower beam than the Blast. The Blast is a wide spot similar to an Arc LSL with about the same overall brightness, i.e. somewhat brighter than a 2AA Minimag with stock bulb. The package claims 16 or so lumens output, similar to the E1's rating, but I think Surefire's measurements are more conservative. The Blast lamp is supposedly 1.2 watts vs. around 2W for the E1. The Blast gets somewhat more runtime from its 2AAA's than the E1 gets from its 123.
As for size, the Blast is a tiny bit smaller and considerably lighter than the E1. And at current sale prices you can buy more than ten Blasts with batteries for the price of a single E1.
The Blast is maybe not the absolute best of the pocket lights, but it's a very good value, and everyone should have a few of them.