First off, don't listen to anything anyone says about the place who hasn't been there in the past couple years. It's altogether different than it was and is now a very nice place with all of the upgrades that were made.
It's kind of on the medium to sort of small size for what would be an arena or pavillon show. It's big but managable if you happen to be turned off to that sort of thing. It's actually rather pleasant with the trees surrounding and the 9:32 bar or clubhouse area (which reminds me of a beach house) is a halfway decent get-a-way for a drink with DJed music. The food concessions are a bit better than most venues. Everything is pricey just like it is everywhere else.
The sound is pretty good, even on the lawn, for outdoors. Just don't wander too far to the sides.
You're still going to be watching ants perform onstage if you end up on the lawn but the pavillion is rather nice, especially the closer you get. I've never been in their pit but I would assume you would like it if you don't expect a seat to come along with that. The stage is big so you will have to do a lot of head turning to catch everything if you are in the center.
As all other larger venues, the ticket prices inside are usually high which prevents me from catching all that many shows there. As far as the lawn goes, I personally won't buy an advanced ticket solely due to potential weather factors. If I miss out on a last minute ticket, than that's my luck and far from my only losses.
All in all, if you are considering going, do it. It's a nice place. Even I like the place and I usually can't stand larger venues. In fact, I didn't like it much before the changes but it's a whole different and much better place now. I'm sure you'll be happy if it's a show you want to see.
If you go in from Baltimore, the traffic will generally be no problem at all. It's all those coming up from the DC area who hit lots of traffic but nothing like Nissan entire day pilgramages. Just your normal periodic traffic jams.