I too attended Vertica, and I must say: this appears to be the FIRST column based database vendor to _get it right_.
For those of you who don't know me: I'll tell you this, ask my friends - I will tear up the marketing material and look for all the pieces to be in good working order, and technically sound/stable before I give my word on something. It's just who I am.
Vertica has got me excited, the first database engine to actually get me excited since the 1980's... ok... the early 90's... Anyhow, it was a pleasure to see that Vertica has thought about the loading performance, right along side the query performance, right along side the ability to query DEEP OR WIDE at the same time. Through some proprietary technology, and internals that I cannot discuss - they've managed to overcome many of the achillies heels that have struck the other VLDB/MPP solutions in the past. Like Shawn, I too was _very_ impressed that they already had 50 customers (big names) when they came to present.
I hope to see more on Vertica as they grow.