Well my crackberry brethren the Onyx went to field testers this week with at&t. I apologize in advance for this being long winded. I wanted to try to provide as much detail as I can. As I was a tester for Bold last year and some others over the years I will provide my observations.
First off I measure this against the Bold. The bold was the most advanced blackberry and IMO most advanced smart phone when it debuted last year and that it continues to hold that title. Since the Bold was released for testers in July 2008 I have used 12 other devices (some BB, some WM, and 1 iPhone) when testing completed I put them all back in the drawer and went back to my Bold.
Item 1 size: The Onyx size is very close to the same size as the 8900. I have a picture of it next to my Bold and a picture of it next to the 8900 that I will try to post on this later in the weekend. I find the size nice to handle, I have an average size hand and average size fingers and I find this very functional from an ergonomic standpoint.
Item 2 keyboard: The keys are a little closer together than what I was used to on my Bold but I don't find that I make mistakes with any greater regularity than I did with the bold. The keys on the bottom row are smaller as well but it doesn't seem to bother me much.
Item 3 back cover: Back cover has a leather (real or fake not sure and I am not sure I care) patch on it. That seems to provide a bit more grip when I have it on the dash or the center console. I also like the way this cover slides into place. I personally didn't have any problem with the battery cover on my bold but know others who have and who also have had problems with the cover on the 8900. I like this one better and it will stay firmly in place.
Item 4 memory card slot: The MicroSD slot is located under the battery cover. It doesn't require a battery pull to access it or anything like that but I did like the bold better the way the card could be inserted from the side. Minor thing IMO and largely a personal preference thing with me.
Item 5 mute & lock buttons: The Onyx places these on the top of the unit much the same as the 8900 and I like that over the mute button on the bold.
Item 6 Track Pad: Yes this device came to the field with the long anticipated track pad. As a veteran if the ball and the wheel I will say this feature is VERY impressive. It takes a very short while to get used to it and once you do your off and running. I do have one minor little knock on the track pad though I wish the button had just a little more resistance as I find that I am accidentally pressing it sometimes while navigating.
Item 7 Memory: For those of you that think this device should come with 512mb or 1gb you'll be disappointed. It comes with 256mb and I will state that this is fine. I don't see a need for more than that, maybe it's just me but IMO there aren't enough useful apps to fill that up at this time so I fail to see the point. So far my application free mem holds at 129.2mb and I don't see any leaks that I can find.
Item 8 OS: The device came to the field with SW 5.0.0.169 on Platform 5.1.0.30. One of the reasons that I am fine with the memory is that I believe this OS does a much better job at memory management than the bold. The device is quick, very responsive, don't see lag times things of that nature. There are a few minor little SW bugs that I won't go into as they are already being corrected and again they are minor IMO.
Item 9 Features: There are many similarities between this device and the Bold and Bold users will be comfortable finding things in the same places for the most part. There are a couple of cool things that I like that have changed though. For those that like to use different ring tones and assign them to people you will find that the tasks of assigning ringtones is much more user friendly now that it was with Bold. Another thing that I REALLY like is that you can now also set message tones for people individually so that you can tell if a message comes in from someone important (assuming you assign them a msg tone) or it's just another message from someone else. I like this feature myself as I use this device for work and often get 1500+ messages per week with about 5% of them being ones that I think are important enough to pay attention to.
Item 10 Screen: I am not sure technically if this is the same screen as the 8900 but I see a big difference in clarity between it and my Bold. Though slightly smaller it's very good.
Item 11 Media: The way this OS manages media is much improved. I got rid of my iPod when I got my Bold but I listen to a lot of podcasts and always had a problem with the way it managed them as it would never group them by date always in some weird order so I would have to go into iTunes and set the order that I wanted them played before I could launch media sync and update. This is fixed and it seems to sort things correct now on the 9700 (OS 5.0).
Item 12 Network: Spent most of my time in a 3G environment and the device does very well. I don't see any degradation between the bold and the Onyx when it comes to 3G service and IMO call quality seemed slightely better on the Onyx.
Item 13 Battery: Ok so this is an area that I was very suprised about. Again I spent most of my time the last few days in a 3G environment with Bluetooth on and connected to my Jawbone II. Battery life seems greately improved from the bold. Similar environments on the bold would result in battery at 50% after 8 hours. I did a hard test as I was out later on Thursday and saw battery life at 70% after a full 16 hours with normal use. Note that I use a display backlight setting of 10 on both my Bold and Onyx as I find that is all I need.
So that is about it in a nutshell. I am sure there are many specific things people here will like me to test and I am happy to do what I can. As I get updates and find more things I will continue to update and I will get some pics up as soon as I can remember the password for the place where I was hosting pics before

it's been a while since I had occasion to upload pictures.
To sum this up for me I see nothing about this device that would cause me to take my Bold out of the drawer anytime soon. Onyx has become my new favorite device.
PG