I just got an E200. I got free from Smart since I've had the E100 for two years and beside the obvious difference that it's new and my old one was a dinged, banged and scratched excuse for a smartphone, here's what I've noticed:
Battery life: The E200 eats juice like there's no tomorrow. If I don't recharge within the day, I'd have about a bar of battery left (15-20%) by night time. And that's with minimal call, text, browsing. No music, no sd card, no screen saver, silent (no vibe) profile. However with the charger adaptor innovation, I don't need to bring the USB cable all the time, just the charger.
Camera: Image quality remains the same. But now you have the option to have low quality with 4x zoom, medium quality with 2x zoom or high quality without zoom. The fact that the camera is now internal has made the SAP comparable to Nokia Cam-Phones (we all know how it was with the E100). The record button can now be used as capture button so you can hold the phone like you would a digicam, quite a nice touch. Video wise, frame rate is greatly improved.
*on the otherhand, I took advantage of the way the E100's camera attached to the bottom of the phone--you can use it to look around corners, cubicles, walls without exposing too much of yourself or your phone--sort of like a recon instrument.
Smart Explorer: The E200 comes with its own version of this, the File Manager. Almost the same, I'm sure there are pros and cons about the UI, but so far I've found their functionality to be equally matched.
The Voyager also has a few other software pre-installed that replace the user-installed versions. again, their similar, but not exactly the same, so it takes a bit of getting used to. And again, funcion-wise, they both get the job done.
Clear Storage App: I think this serves as a Hard Reset App, but I haven't tried it out.
Java Midlet Manager: Unlike the E100, the Java apps are now quite at home with the Voyager. I haven't tried it with JARs or other Midlets
The Windows 2003 OS is also a bit more responsive than the 2002, and you can monitor how much RAM or PF you're consuming and when you need to restart before your phone hangs. Aside from that, old apps like the Addict Mobile Menu (STK Service) now has an exit button.
Inboxes are categorized to Active Sync, Email, and SMS. And you're given the option to handle multiple email accounts.
All in all, I think there are about 7 or 8 previously user-installed apps that are now native to the E200. The OS is around 15-30% faster. The Joystick and Soft Keys look and feel better. And the keypad light is now blue. I guess you could say I'm happy with my Voyager--then again, I was happy with my Tanager. If Smart didn't give it out for free, I wouldn't go out of my way to buy it.
A final note, there's an Unlock program specifically for the E200 that I picked up from one of the threads a few months back. Works for the Voyager without a hitch.