The update has not done great things for my connectivity, to the point that T-Mobile are insisting that they send me a new phone, but now that I have had it a couple of days I do actually quite like the way the operating system is laid out and looks. I like the way it keeps a notification for Bluetooth in the notification bar so you can get at it more quickly. Apps which were not running well on 7, presumably because they were being optimized for 8, are running better. Waze navigation is one example.
The workaround I found for the no network connection issues I am experiencing is to select 3-g 2G network instead of the default with LTE, at which point the 4G icon and 5 bars of strong service show up. It's really really weird, but it should tide me over until they get me a new unit. The truly strange thing is that by selecting the slower Network it is actually running faster than it did before or after the upgrade! As yet nobody has figured out what the heck is going on. It confirms my experience operating system upgrades are invariably more trouble than they are worth! I only did it because the phone kept nagging me...