1) Get your permit way ahead of time, and get them to send it to you so you have it in your hand. I tried all week to get hold of them and they were either closed or wouldn't answer their phones. I finally talked to someone and they told me to send in my application, which I did, only to find it still not available Sunday morning. Fortunately they had a late-arrival permit available.
2) There's a temporary re-route of the main trail, going up the wash for the first half mile or so. If you pass the ribbons, you've gone too far, even if you still see footprints in the sand (that's from people heading up to see the falls). Most importantly, as you're heading up the wash, it's a **left** turn to head up the side of the canyon, unlike what many online resources say.
3) it's colder at the top than you might think. I went up just wearing shorts and T-shirt (with fleece in my pack), laughing at the SoCal wussies coming down from the summit with hoods up and gloves and long pants. It took about five minutes at the summit before I had that fleece on.
All that said, pine trees! Lush grasses along the high creeks! Clouds and cool wind! That's what I went up there for. Apologies for the picture quality below (here's the whole album). From the summit you can see the Salton Sea. To the west there was smog and some clouds coming in. San Jacinto is right across due south and Big Bear Lake is quite clear to the northwest, and the wind turbines along I-10 north of Palm Springs are right below you. Of course none of these came out well on my dirty iPhone.