Oooo...I'll put some first thoughts here too since I've been asked a lot lately.
I really love all my games so far. Motorstorm Pacific Rift is excellent, but it has that online setup I hate. Still very fun though. Competition online in ranked matches is fierce.
Metal Gear Solid 4 is fantastic as I expected. I'm in the beginning of Chapter 3, which is the first time I'm getting a little annoyed with this tailing the resistance guy bit, but the story is awesome. Plus Otacon finally gets some! MGO I haven't even tried yet, because the setup to get in is worse than using Friend Codes on Wii. Seriously Konami, shame on you for your bullshit online process. I've got enough games to play online anyways.
Warhawk is perfect. I didn't expect it to be my favorite. I just found it cheap at Walmart for $30 with the headset so I scored it on a whim. It's one of the best onlines I've ever experienced.
Now to the system itself. The XMB is nicely setup. I'm familiar with it because of my PSP. Free themes are awesome. I've got some big boobed chick from PAIN and she's got her ass haning out of a pair of daisy dukes. She moans when I click on an option. Very nice!
Now to some things I don't like:
1. Content-It's just not there. There are less demos on PSN by a wide margin. A lot of PSN games don't have demos and I find that to be a bit odd. Every XNA and XBLA game has a demo mandatory and I would have expected Sony to make them mandatory also. Guess not.
2. Mailbox-Maybe I'm just a dummy and I don't see, but there doesn't seem to be any notice that I have new mail. Sure I get a quick pop-up when it comes in, but if I'm away or my kid is watching a DVD on there, which is often, I'll need to go into my mailbox to see if I got mail. On top of that, you get no indication on which have been read and which haven't. They don't bold and unbold the titles to help tell the difference.
3. Downloading-It's takes forever. It took my over an hour to download the 2.1 patch for MGO today, and that was all for naught, so it was especially annoying. Demos take a good 40 minutes for approx 700MB-1GB of demo. That's before the install, which I find to be very annoying. If I go away while my PS3 downloads demos, I'll still need to sit through an install process, which is like 4 minutes itself once I'm back. Couldn't that have all been done in one fell swoop?
Overall though, these are minor things, and don't take away from what really matters, which is kicking ass in Warhawk. Warhawk rules!