Haven't got much experience with the TyTn or P990i, but I CAN tell you that the E70's latest firmware seems to be a bit buggy - not nearly as stable as my 6630 with frequent crashes etc. Its also sometimes pretty sluggish - screen redraws happen slowly, expecially when you flip it open.
While on a call, the switch-to-handsfree soft-button is gone (replaced with Mute?!). You now have to dig down into the options menu for it - extremely irritating if you want to quickly grab a call while driving.
Also, good luck in finding a pouch for it
But all-in-all, I think its a great little device + most of my gripes would likely be solved by a future firmware update...
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