I've had the phone almost a week now, and I can tell you I very much enjoy it. Is it perfect? No. But, I do like it better than my 700wx that I had.
You have to tweak this phone to make it more usable, but once you do, it is probably the most advanced phone available. I'm not with Cingular, but I think these phones are much more capable than an iPhone for example. At least we have high speed internet.
My main pros:
Very compact, small footprint, and NO external antenna (Yay!)
Brilliant, crisp screen (better than the 700wx which almost looks washed out in comparison. 240x320 has more compatible software).
WM6 is prettier and more functional. (Not revolutionary, but definitely some nice improvements.)
Wi-Fi (Never really thought I would use it, but it comes in handy when I visit friends and family outside of the EV-DO coverage.)
The slide out keyboard is roomy (I've really gotten proficient with it in just this first week.)
Standard mini-USB charger that can be bought anywhere (I picked up one at Target for $10. That was after I spent $30 for one from Sprint when I ordered the phone.)
Bluetooth 2.0 works better and has a better range. (I can now keep my phone on the opposite side of my body without much static. My 700wx was nearly intolerable doing this. Also, my headset is louder than with the 700wx.)
Good camera mode. (Not great quality, but I like how you hold the Mogul sideways and shoot like a point and click camera.)
Numerous remappable external buttons (But NO volume rocker.
.)
Jog wheel makes scrolling quick and effortless. (Still need to use the 5-way to go right or left though. LEFT mounted scrollwheel!??)
Now for the cons:
No volume rocker button or easy ringer off switch like the 700wx. (Someone did write a small app that lets you use an external button to quickly do this though.)
No exposed keyboard (Obviously. But with picture speed dial and my other tweaks, not a big loss.)
Onscreen battery gauge takes up a line on your Today screen. (I liked the battery gauge in the top bar like the 700wx. Once again, there is a free software tweak which will place a very thin multi-color line at the top for your battery gauge.)
As you can see, no phone is perfect, but spec wise, the Mogul is the most advanced WM phone available today. It's EV-DO capable, and will be Rev A by this fall, making the internet even faster. The main key is, be prepared to tweak this phone. Out the box, the 700wx is easier to use. But once you get the Mogul set the way you like, it works like a champ. HTC did a very good job.
Here's a list of some apps I put on my Mogul:
HTC Home (Today screen plug-in from the HTC Touch)
Calendar+ (Almost a necessity. It's free and it really expands on the built in Calendar. I used this on my 700wx too.)
Photo Speed Dial
HTC black theme
SMS Threaded App