Interesting topic going on here... guitar's been my life since I was 10 years old. Anyway, from experience you can't decide whether a guitar is good or not by the brand. Brands mean nothing for acoustic guitars, unless you're talking about Yamaha/Ibanez; you have to actually play many to decide which is good. When buying an acoustic:
1. Decide what your budget is
2. Check *every* guitar that falls within your budget (and in multiple stores)
3. Check for fret buzz by playing all over the fretboard - very difficult to get rid of buzz and almost 50% of guitars that are on the shelf have fret buzz
4. Action is secondary as you can always get it setup professionally later (it's actually a necessity if you can't do it yourself)
5. Check the keys to make sure none of them are lose - if they are, you'll keep running out of tune frequently
6. Finally, guitar care is very important once you get one; buy a good case because keeping the guitar out increases the chances of the fretboard getting warped over time
There's more tips to take care of a guitar once you get it... this is just a beginner's guide
Hope this helps...