On the surface, this appears to be a good phone, and there's nothing to tip you off about two major flaws in any of the reviews or documentation available.1. You cannot store multiple entries for the same 10-digit phone number; for example, parents who live at the same house but carry different cell phones, or business contacts with the same main number and different extensions. Nor is there any provision for dialing an extension automatically after a main number. Say you deal with Tom in Marketing at 111-555-6666 ext 222 and Mary in Legal at 111-555-6666 ext 333. Most phones will allow you to insert a non-numerical character to indicate a pause before dialing the appropriate extension. Not so with the T610, which only allows numerical characters. Both Tom's and Mary's numbers would both be stored under Mary's entry in the phone book, and you will be, as I am, carrying an additional notepad with all their extensions on it.ADDENDUM: Thanks to Brightcell's contribution, I know how to insert a pause after a main number. :) However, the phone strips off non-numeric characters when importing from a PC address book, and there's nothing about "pressing and holding 7" in the T610 manual. Neither T-Mobile user support nor technical support was aware of this feature. To be completely fair, I tacked on a star to my overall rating.2. If you access your voicemail 20 times a day like I do, expect a lot of unnecessary keystrokes. Instead of a simple voicemail indicator flag like most phones, the T610 provides a text message (an e-mail) indicating you have a voicemail. You must read and delete this, then back out to the main menu to access your voicemail. The options menu for the e-mail message includes "Call Voicemail"...but this doesn't work owing to some incorrect programming (and I have verified this with T-Mobile tech support).ADDENDUM: Brightcell's contribution not withstanding, T-Mobile support confirms that there is no way for a user to turn this "feature" off. Their tech support rep offered to turn off voicemail notification altogether, which I declined. This, they said, was the ONLY way to make the notification e-mail stop. If pairing with T-Mobile service, be aware that they do not know how to make their service work properly with these phones.There are actually a number of other minor issues with this phone, including intermittent Bluetooth connectivity, a microphone that picks up every last bit of ambient sound and is almost impossible to use in a car, the fact that the battery wears out quickly even in "lock" mode because hitting any key activates the backlight...but all these things I could overlook, were it not for the two major issues above. On the plus side, it is small, cheap and has SOME kind of Bluetooth connectivity.