I visited the convention center as part of the expo for the Rock N Roll marathon/half marathon and this review sprawls across both of these entities.
As for the convention center, it's certainly in the upper half of "Convention Centers I have known". The rooms are spacious and it's easy to get up and down floors. The design is nice with easy access to the stairs and escalators and they have the exit-only designs that are conveniently located. It may not be the greatest endorsement when I say that the convention center can be quickly exited, but I appreciated these benefits.
The Rock N Roll expo was also reasonable: they have a similar set up at all their races and the number and scope of vendors is impressive. Now, I've always considered these things the equivalent of runners' porn and typically try to get out as quickly as possible. It only takes a momentary distraction to have you stop in front of a stall and decide that you must have the new Saucony socks ("But these are ULTRA wicking!")
I've taken the Jason Bourne in an embassy in Switzerland approach: when you walk in the entrance, you put your earpiece in, rip the diagram of the building off the wall, analyze the quickest route between the points you need to go and then march. This typically works fairly well and you can navigate through the whole affair in a few minutes. Not too shabby.
A friend of mine has a different philosophy. He claims that you want to take the more circuitous route through the hall since people tend to congregate in the center of the place. He probably has a point (although I'll never admit that to him): there's actually a hierarchy of vendors and the less desirable ones tend to get stuck along the back walls. When you navigate this path, the crowds are sparser and the vendors are listlessly standing next to stalls of "Used Running Socks" and "Backwash Gatorade". I tried this manuever at the Phoenix expo and found that I could exit the building a little faster. An idea to try the next time you're at one of these things......