I had been running the A620e with a Telecom connection since the 10th December, and switched over to the A620b yesterday.
Most notable differences are signal strength and battery life - considerably better with the A620b if you have a Telecom connection.
Phone updates are working successfully as well......the A620b is running Firmware revision number: 1030.54.10401.781 whereas the A620e is running Firmware revision number: 1030.54.10403.707
They are both running the same Radio software version: 1.11b.3054.25_10.13.30.54P
Have just applied 6 updates that the Store automatically identified including both an "HTC" and "regulatory" updates.....and this has updated the Firmware revision number to 1030.54.10401.781....and the Radio Software Version is unchanged.
There are only two issues I've had with the 8S sofar.
The first is a BSOD with Internet Sharing from my Windows 8 Notebook which is running an Intel Wireless Wifi link 4965AGN - works fine with the Nokia Lumia 800 on v7.5....but needs a workaround for both above variants - see: http://answers.microsoft.com/en-us/winphone/forum/wp8-wpnetwork/windows-phone-8s-by-htc-internet-sharing-causes/dbed2eca-ac54-4769-94b1-3a2881a86577
The second is opening PDF documents - sometimes they open, sometimes they don't. If I open a pdf from skydrive.....it never opens - known issue and should be fixed with a Microsoft update.
Compared with the Nokia Lumia 800, the Windows Phone 8S is great. It is lighter, smaller, the screen area seems better and so I make fewer mistakes through the OSK.
The Nokia Lumia 920 turned me off just because of the size.
Bluetooth pairing in my car is less flaky with the 8S than with the Nokia Lumia 800.
I am using GPS Voice Navigation as an alternative to Nokia Drive and @ US$10 is pretty good.