I almost didn't upgrade from my 8703e to the 8830. But after a week of 8830 use, I am very glad that I did. The trackball is great (especially as you get proficient and can navigate the menu, etc in both dimensions simultaneously
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Keyboard is not quite as good, but I can use it well after only a week. Backlighting/key color combo is bad, but if I slightly adjust the angle of the device when using it in the dark, it is fine for me.
I bought the seidio slim case before I had the device. I actually like the leather case better for my day-to-day use. I pop it in the seidio when I want to go ultralight (and the combo is very light - as previously mentioned by others I can clip it on workout gear and it is very comfortable).
Ring and vibrate are a little low for me. I almost always have it on vibrate, and have only missed one alert. I followed the other thread and called VZW to report my complaint about ring/vibrate.
At then end of the day, I am very glad I switched from 8703e to 8830. And I almost didn't do it. What pushed me over the edge was a comment from someone about bluetooth volume being much better on 8830. I can confirm that this is true on all of my devices.