Pros: Plenty of jobs in the high-tech industry. Even though Austin is one of the most expensive places to live in Texas, it's more affordable than many other metro areas in the country. Ozone action days are on the high side, but again, compared to many other metro areas, the air and water quality are pretty great. The weather is very nice from about October-March. Very mild. A nice bonus is that Austin is fairly vegetarian friendly (it's no NYC, though, let me stress). The airport is pretty easy in terms of parking and lines. There are tons of health care options. No need to drive to another city to see a specialist.
Cons: Traffic is horrible at rush hour. Not much in terms of public transportation. But personally, for me, the worst two things about living in Austin are the very hot and long summers (yes, with humidity) and being land-locked. Allergies are also horrible here, and the schools seem to be in trouble. Lots of budget problems, school closings and teacher lay-offs lately.
There are basically two seasons (in my opinion) - 6 months of summer and 6 months of sorta spring. It starts getting hot, in the 90's as early as late March, mostly starting in April, and stays hot (mid-high 90's) through September. It is very frequently in the high 90's low 100's May - September. October - March is pretty mild, although it can get below freezing at night, which is actually refreshing for me. Generally, for someone who likes 4 seasons, it's no fun. For someone who loves the vibrant colors of autumn, it's downright depressing here.
The closest clean beach is about a 7 hour drive to S. Padre Island. I've been to Corpus Christi once and was not at all impressed by the large signs on the beaches that provide instructions for removing oil residues from your body. This was BEFORE the gulf oil spill disaster. There are a lot of lakes and fun river activities, but it seems like we're always in a drought.
If you're from the east coast, or somewhere similarly populated and connected, and you're used to having tons of choices for day trips or weekend trips by car, bus or train, then you'll also dislike being stuck in the middle of Texas, where Houston is about 2hrs, Dallas over 3hrs, and San Antonio being the closest at about 1.5hrs away by car. And again, the cleanest beach is about a 7hr drive. Everything in between is pretty dull, especially if you happen to be a vegetarian. Good luck finding a place to eat in a small Texas town. If you can afford to fly often, then it's probably not a big deal. There is also an Amtrack station and a Greyhound bus terminal, but those will just take forever. Certainly you're not in the middle of nowhere, but if you're used to being more connected, like along the north eastern / mid-atlantic coast, it feels isolated.
Overall, Austin is a great place to live if you can tolerate the heat and are content with the somewhat geographic isolation.