In a nutshell, Pros: Pure Android, no carrier bloatware or manufacturer overlay. Updates are faster and devices are supported longer. It's reasonably priced and NO contract required. Esoteric bragging rights.
Cons: It can be a little stark out of the box. Not too much eye candy, but plenty of potential. That can take some research and work. Support through Google meaning you can't walk it into your local carrier store with a question. They wouldn't even know what it was.
SD card or not, backups are very important. Because the memory model in JB virtualized the volumes, even a factory reset will delete user storage. Many will sync their files to the cloud and then sync them back after a reset or flash.
Build quality is excellent, although the flat glass back will muffle the speaker if laid on a flat surface and it makes the phone slippery. LG has added little bumps to the back edge to fix that, but some are still getting the smooth model. Not a huge issue, but an issue nonetheless.
I haven't really had any signal problems, so I'd say it was on par with every other phone I've had, although the GPS will get a lock much quicker than any Samsung phone I've ever owned.