How did it go?
Sorry to have missed this thread earlier. Always better to buy in store and spend as much time trying them out as you'd like, ideally in a private audition room so that you can hear the guitar.
1. Know your budget
2. Don't be afraid to choose with your eyes
3. Be brave to decline a guitar that you love the look of but just doesn't click
(this is starting to sound like relationship advice)
4. Pay attention to how the neck feels, sharp fret edges, the action, intonation up and down the neck
5. Sweatwater seem like good guys, tell them your playing style, budget, and ideas and ask them for some conservative and left-field recommendations. A good sales person will listen to what you want, never speak down to you, and give you sufficient time to make your choice. If they're really good, and your budget covers Taylors and Martins, then they'll be good with coffee etc.
6. Enjoy the day out! I schedule a whole day to find a new guitar. Useful to take a break for lunch before going back and taking your top picks for a second date!
Chris