Here's what my impressions of the Hero are so far. Keep in mind that I am coming from javing a HTC Mogul WinMo phone for 2+ years, and had a tame Samsung non-smartphone before that.
Looks very sleek and well-made. The trackball is a little weird, sticking out and illuminating as it does. Hardly any buttons. Feels good in the hand - not cheap/light, but decent weight and finish. Tilt is the opposite way of the Mogul, which is a bit strange to me.
The home screen is functional and probably perfect for most users, but can be customized. You have 6 other screens available - 3 to each side. Defaults are okay, but I soon customzied them all. Customization is easy, but takes time. I can see spending a lot of time back and forth as I use it until things fall into place the way I want.
On using the device, I primarily use touch and rarely the trackball. In fact, the trackball seems unnecessary. The onscreen keyboard is pretty good - can use thumbs in portrait mode pretty well. Landscape is better, of course. It autocorrects as you type, so most fat-fingers are taken care of. However, beware because it may 'correct' a word you thought was okay, turning it into a completely different word altogether. Once you figure it out, it works well. I do miss my hard keyboard, but this might work. You can use pinch gestures for zooming in some apps.
On applications, it comes with a nice selection. Integration with Exchange servers works well, as does Gmail, Gcal, etc. In fact, you can have your work appointments synced with Exchange at the same time you have your private ones synced with Gcal. That's a nice feature. Twitter, Facebook, Flickr, Aim, Y!M, Live Mess, etc integration is all there and seems to work just fine. Text messaging, contacts, and email all work well. Media player works fine, Youtube is excellent.
Android Marketplace rocks. Very easy to browse for new apps, see what they're about, view ratings, and also get the security warnings for what they access (network, contacts, camera, GPS, etc). Tons of free apps to download, and they do so in the background while you continue to shop/etc. Most of the pay apps/games I saw had free trials (or ad support) and then a low $1-2 cost. I grabbed some games that looked interesting and then most of the apps mentioned above.
Notifications - text messages, new tweets, etc all show up in the top status bar while you're doing other things. You can read the first part of the text message, for example, right there. You can drag that bar down to show the notifications, or use the menu to get to them. The indicator lights don't blink unless you have a new notification (or have configured them otherwise).
Configuration - lots of options, most are straightforward. Some seemed kind of shallow, I'd like to dig deeper or configure more granular options.
Battery - I have no idea under normal use, I've been draining it by playing with various things.
Voice - seems fine, I've only had 2 calls and haven't experienced anything particularly good or bad.
Issues - Still fighting the tilt direction and virutal keyboard - want a physical one. Don't like the limited calendar display options. Haven't figured out how to configure Exchange sync to certain hours.
Overall - This is worlds above WinMo. Android is where it's at. If the iPhone is anything like this, then I can begin to see the attraction. I will either keep the Hero or perhaps try the Samsung Moment on Nov 2 since it's Andriod with a real keyboard - either way, I'm staying with Android.
Now to go find other fun apps and reconfigure my pages. I may even start working with Scenes, which basically expands the number of screens to 49.