Trying to clarify some things
To me it seems that most Americans don't know that "Wideband Audio" feature. So I'll try to enlighten you
This is not Apple leading something, but it's quite common since about 1.5 years, at least in Europe. Some providers are pushing it quite actively, but it's mostly known as the marketing brand "HD voice". Most people know it under that name because that's what providers use. The used codec is called "AMR-WB" (Adaptive Multi-Rate Wideband), but no one knows except a few nerds
Listen to this and then you'll understand why it is so cool:
http://www.youtube.com/watch?feature=player_embedded&v=bwVPkt6vwEw
In Switzerland (where I come from), 2 of the 3 providers support it on their 3G network (Swisscom and Orange), but not yet in calls between those two networks. In most countries in Europe, 1 or 2 networks support it.
Except the network, you also need a Phone which supports it. Most current premium handsets do. My provider offers those in his own shops:
http://shop.orange.ch/en/phones/icat/phones-hd-voice, but there are more.
Until now there was one big player missing: Apple. Now, they are catching up.
I also filled out a feedback form on the Apple home page directly after the iPhone 4S came out without it, and I know I am by far not the only one.
About LTE:
Many European providers are in the early stage of deploying it. So, except a few countries, we are way behind the US in that respect. The reason is mainly that there is not much need yet. All European providers have GSM/UMTS/HSPA networks, many are now on 21 or 42 Mbps and they still have some air left with that (HSPA+ is specified up to 168 Mbps). So they don't have the problems of Sprint and Verizon which is CDMA2000/EV-DO which limits them (maximum spec. is 14.4 Mbps).
The iPhone 5 will support hardly any of the European LTE networks, because the common frequencies for LTE over here are 800MHz (Band 20) and 2600 MHz (Band 7), which are not supported by the iPhone 5 or new iPad. EverythingEverywhere in UK and T-Mobile in Germany also operate networks which use 1800 MHz in some spots (Band 3). This is why the iPhone 5 works at those spots.