I know at this point most people are waiting for the new devices coming next year, but if anyone is still contemplating getting an Inc or an X right now, I thought I'd add my thoughts. I've had my DX for a week now after having an Incredible for about 3 months (and a Droid 1 before that since launch). This isn't meant to be a complete review of the features since you can find that anywhere, just some pros and cons and the small things I noticed between the phones.
- The AMOLED screen is beautiful. Vibrant colors and great clarity. However its very hard to see in sunlight (or outdoors in the daytime in general) even at full brightness. Not sure how the newer LCD based screens are though.
- HTC's Sense UI is butter smooth and has some great widgets. Definitely much better than stock Motoblur.
- Sleek form factor. The phone is very thin and fits great into your hand.
- Battery life is terrible. The stock battery is too small for this kind of phone. The extended batteries are nice but ruin the sleek form factor. The phone's software also apparently prevents the battery from truly charging to 100% (read about bump charging)
- Notification LED sucks. It can only be green or amber, and is somewhat inset into the phone so you can barely see it at an angle. It also seems to turn off after a while even if you haven't checked the notification. The only pro here over the DX is that its also used a charge indicator so you can easily see when its done or not. The D1 has a small light near the charing port, but the DX has nothing.
- Phone is plastic and feels somewhat cheap. It is very light though.
- The entire back of the phone is the battery door. This is a small pro since if you scratch/damage the back of your phone, you can pick up a new back for $10 or less and make it look like new again.
- SD card is not blocked by battery. It's inserted on the side of the phone beneath the back door.
- Very few accessories (other than cases). This seems to be the case with most HTC phones. No true drop-in desktop dock (or dock mode on the phone).
- Camera lens sticks out from the back so the phone rests on it (same way on the evo). I can see this being a problem for the camera long term.
- Camera does not have a manual focus (in part to having no dedicated camera button) which was sometimes annoying
- Optical joystick was nice for precise cursor placement when typing. Didn't use it for much else.
- 4.3" screen is awesome. Like most people I was worried the phone would be too big, but its definitely not. I don't think I'll ever be able to go back to a smaller screen. However, the actual screen isn't quite as nice as the Inc's - less contrast and a bit duller looking. The first time I played Angry Birds it felt like the level was being played on a cloudy day compared to the Inc.
- Motoblur feels laggy and slow compared to Sense. The stock widgets aren't as nice either. However, this is a non issue, because you can use LauncherPro to make the UI even better than Sense, and for a measly $3 you can get LauncherPro Plus which has most of the Sense widgets.
- Form factor is debatable since its 4.3", but as I said above its definitely not too big (for me). Phone is just as thin other than the top hump for the camera, which actually makes holding the phone feel more natural if you rest your index finger below it.
- Battery life is better. The stock battery is bigger and doesn't drain as quickly. However, battery amount is only reported in increments of 10%, where as on the Inc it was every %.
- I've had more lockups and battery pulls in the week I've had my DX than the 3 months I had my Inc. I'm blaming this on the motorola firm/software.
- Physical buttons are subjective. You really just have to try them yourself and decide. I don't mind them though.
- Phone can be unlocked using the home button. I find this much easier than using the power button. I also have a widget to lock the screen since it is a bit of a reach to hit the power button while holding the phone normally.
- Phone is metal and feels much more durable than the Inc.
- SD card is blocked by battery.
- No charge indicator compared to the Inc (and OG Droid)
- Better call quality. I was told by a number of people I sounded clearer on the DX, probably because it has 3 mics to the Inc's 1.
Note: I haven't rooted/used custom roms for either phone, so that was not a factor in any of my above points.
In summary, when I got my X I was afraid I was going to have to deal with a somewhat clunky UI in trade for better hardware, but I was very wrong. LauncherPro (or ADW, etc) can make the phone just a smooth and even better than HTC's Sense.
The bottom line IMO is that if you can handle the size of the DX, its the clear winner over the Incredible.