LTE has been great so far because of its speed and because it brings high speed wireless Internet to the German countryside. One major downside of LTE on my smartphone so far, however, have been the very long call establishment times for incoming and outgoing voice calls due to the required fallback to GSM or UMTS.
In practice I observed typical CSFB (circuit switched fallback) times of about 2.5 seconds in live networks in addition to the normal 3G call setup time. A call from an LTE to LTE smartphone thus takes 5 seconds longer than a 3G mobile to mobile call establishment, which is around 5 seconds. 5 vs. 10 seconds, it almost felt like eternity.
Recently, to my surprise however, setup times have significantly reduced in my network of choice and CSFB calls from between two LTE mobiles are now established almost as fast as pure 3G-3G calls. The difference is around half a second at most. Something that one can quite live with.
Kudos to the network engineers, LTE is now finally usable for me on smartphones!