I am not totally into quads but do own 4, with all the different manufactures that have sprung up making quad frames how do you decide, or what do you look for in a frame say the 250 size. The choices are endless and growing.
First you decide what kind of flying you want to do, racing or freestyle (including normal flying). Racing frames are more minimalist with thin arms and small center sections. Freestyle frames are often bulkier so withstand harder crashes and fit more gear like an HD cam. At this point there seems to be a lot more race style frames than freestyle frames.
Once you've decided what you want to use it for, and even if you haven't, it really comes to what appeals to you. If you like how a certain frame looks, that's a reason to get it. If you want to support a local vendor, get one of their frames. Unless you're buying really cheap from somewhere like aliexpress or banggood, most frames will be decent or more quality.
Another thing to note is compatibility. If you want to carry a GoPro, make sure you get a frame that can carry it. Maybe one with a built in camera angle like the Armattan Chameleon/Rooster. If you wan to fit 4 individual ESCs and a PDB, instead of a 4-in-1, make sure you pick a frame that can fit the ESCs on the arms and the PDB below the flight controller. If you want to fly 6 or 7 inch props, the options list gets much smaller.
And before you choose to buy, especially if it's expensive, make sure to check out user reviews on product pages and on Youtube. They might point out a characteristic of the frame you don't want. For example, I was really interested in getting the Ummagawd Remix freestyle frame and loved the way it looked. After reading and watching some video reviews I discovered that that frame puts a view of the props in the HD video. Some may like that, but I really didn't, so I ended up going for the Armattan Rooster, which is similar in shape, but different in construction.
If you need ideas, check out the multicopter Reddit, or Rotorbuilds.com.