I build acoustic guitars in a custom shop with a friend of mine. We build guitars based primarily on the Martin pattern, with some custom changes.
You can get nearly any sound you want, depending upon how you create the guitar, by choosing tonewoods, body shape, bracing and construction methods, and soundhole diameter.
I'd recommend going to the store, and playing the various guitars, measuring them for dimensions, and inspecting the construction techniques inside the body, with an inspection mirror. Generally, you'll find that the guitars are rather overbuilt for strength, and are not as responsive as a custom guitar(unless you go to the expensive "custom" production models). The guitars will vary in sound and responsiveness, even in the same make/model line, depending on how well it went together. You could pick up 2 "identical" Martins or Taylors from the same rack at the store, and they sound and play different. Pick the one you like. I've seen some folks go into a store and spend all day playing every Martin in the store, trying to decide which one suits them best.
Taylor braces differently than Martin, and this will influence their sound characteristics. Both are good, and different people could prefer either one.
Generally, you could look for a nice tight grained spruce top, and a non-laminated tonewood body, preferably a rosewood variation. A dreadnaught will be a big deep sound, and the smaller bodies will be more "midrange-y". A larger soundhole will give more midrange out of the guitar than a smaller soundhole. You can "tap" the guitar around the bridge area, to see if it has complex tones that ring, or if it sounds dead. If it sounds dead, it is probably braced so heavy that there is no responsiveness left. Try to pick one that sounds musical when you tap it. A knowledgeable person can go inside a factory guitar(through the soundhole) with a small hand-plane, and shave the bracing until it is good, but that is really only for a luthier to do.
Cutaways reduce the vibrating area of the top, and generally reduce the sound produced, and may limit the bass some.
Check for "intonation" by doing a "harmonic" strike at the 12th fret on each string. If the harmonic is an octave up from the fundamental, and "in-tune" with the fundamental, then it is intonated correctly(for the most part). The B string is the most common one that gets intonation wrong. If intonation is not right, then the guitar will not be in-tune all the way up the neck. This can usually be corrected by a good set-up man. Some guitars are made wrong, and cannot easily be corrected, so intonation is a pretty important thing, if you want your guitar to be in tune when you play it.
Make sure that the neck "set" looks good and tight, and the angle is good. This will reduce the need for truss rod adjustments over time.
Just as in audio equipment, you have to like the sound and feel, so there is no substitute for auditioning and playing.
Everything in your price range is going to be a factory built guitar. You have to find anything that didn't get picked up by the quality control department. And even then, it is going to be much stiffer than a custom built guitar, because they can't spend the time needed on each guitar to make each one as responsive as they could be. They just take pre-cut wood, and put it together, without being able to individually select woods, and individually plane thicknesses, and do alot of hand tuning work. This is why you need to spend some quality time with the guitars, so that you can pick out a "good one" from the batch.
That being said, they are all "guitars", so they will play and sound reasonably good, from those manufacturers. But you can pick out a "winner" for the same price as they charge for the "losers", if you spend some time playing them and listening to them.
Any new or almost new guitar will need some break-in time, and also will need frequent tuning as it settles in.
