In my opinion, the price is high. However, you do get a stitch regulator with it (not sure how good it is) that probably works only with specific Brother machines.
You can get this Hinty frame for about $800:
http://www.hinterberg.com/prod-Origi...g_Frame-5.aspx
It does not, however, have a stitch regulator.
You can use a regular domestic machine on a frame. It's not as convenient as using a machine made for frame quilting for several reasons: difficulty reaching the bobbin, small harp space, need to move the pedal around for larger quilts, cords getting in the way, etc. However, it can be done.
When buying a frame, the size of the carriage will determine what size machine you can use. The Brother frame and Hinty frame above will both probably handle only domestic size machines, which generally means a machine with a harp size of 9" or less. Hinty makes two other frames that can handle larger machines. The stretch Hinty is what I have for a Voyager 17 (17" harp size). It is one of very few frames that can handle the weight of the Voyager.
You can try out frame quilting with a domestic machine to see if you like moving the machine instead of the quilt. However, very quickly you will find out that a small harp size is very limiting in terms of what you can do, especially with quilts larger than baby size or lap size.
Edit: For about the same amount of money ($2,500 to $3,000) you may be able to find a Voyager 17/Hinterberg stretch frame setup that will give you a frame quilting experience that will be more valuable to you personally, and will also have better re-sale value if you decide you don't like it. There are a couple of online places where used machine/frame setups are listed for sale, plus some people find theirs via Craigslist or frame machine dealers (because people will trade in their low-end setup for something higher-end).
Edit 2: I took another look at the photos of the Brother frame. They seem to be using a machine with quite a large harp size. If you already have a Brother with a large harp, then I see the advantages of the Brother frame being (1) it comes with a stitch regulator, although many people do frame quilting without one, (2) it is small in terms of space requirements, and (3) because of the clamping it's possible to quilt a large quilt by moving the quilt around on the frame. Still wouldn't be my first choice for frame quilting, though.