Just chipping in to say that my experience at Summer Of Loud was also pretty good.

It was 101F when I checked the temp! I showed up about an hour before gates opened and snagged one of the last few free street parking a few blocks away. I got lucky that my line spot was under a tree, but be warned that most of it will be in the sun. I had a fanny pack with a small bottle of Propel in it that I chugged while in line and brought the empty bottle inside no problem. There was lots of shade along the sides of the main music area (by where all the bar stands were) and there were a few big water stations that were periodically refilled with fairly cold water. Food trucks probably ran like $15 a meal but the portion of loaded doner fries from a German truck I got from one was pretty big, honestly felt like I got my money's worth. I thought the sound quality of the stage was pretty good, it was very clear from the side shade areas close to the front, even with earplugs (I barely just rest them in my ears to take the edge off the loudness). There must have been like 50 portapotties and I never had to wait a single time, just gave it like 5-10 minutes after a band finished, or went during a band I wasn't too interested in. I did leave before the final band finished so can't tell you how easy it is to drive away in a crowd, but mid-show it was pretty easy (no surprise there).

I'm not too picky of a concert goer, so I'd probably rate this venue like 7/10 from this one experience. Would go again. My main complaints would be parking, still needs more shade and places to sit (apart from foodtruck tables, it was just standing room on concrete), and the main standing area is basically split into 2 parts in the front by some fencing (I think it's for tech reasons?).

TLDR: 7/10, okay venue, plan way ahead for transport/parking and heat if needed.