I've had only a very limited exposure to IPv6, but it seemed to me that the slogan "DNS solves it for you!" doesn't really pan out. It solves it if you're on a well-set-up network and have your DNS up and running happily, but with the ad-hoc networks my [limited] experience has seen, it hasn't been trivial. Essentially, it means you have to run an interpreter service (the DNS) to understand the network - one more bit of software to configure and troubleshoot... though to be fair, IPv4 was also quite confusing when I first started playing with it.