I have both a HT-FPV and a Witespy 450 and have done a sise-by-side comparison of how they work for me. I have made several modifications to the HT-FPV
I will cut to the chase on my opinions -- I like the Witespy 450 a lot better. I hardly ever crash mine...any more. For what I do, which is nature photography and I work in a flight restrained vertical environment and within 1000 feet and sometimes over water, the 450 just works better. Sometimes I put an expensive camera aboard the pod and I want it back if something happens so I do not fly them very far. I seldom have a problem with the 450 and it has proved very reliable. In perilous places I leave the GPS and OSD on the ground. If I am going to hang a very expensive ornament 300 feet up a tree It does not have to set me back $1300! The $700 for 450 plus GoPro will hurt enough but then I have been putting Nikon cameras in the ocean for 30 years so I appreciate risk.
For me - The HT-FPV is a blast to fly and it is very fast, especially if you fly it without a GoPro camera. I love to fly FPV with this frame and have many hours on it. Crows fear me! I have a high-end 600 line CCD flight cam and can fly on all but the darkest nights. However I find the frame to be very twitchy in flight and it does not like downwind hard rudder turns which turn them into Lawn Darts. I cannot make it take good video at slow hovering speeds. It does not handle (or I cannot make it handle) slow, smooth changes in direction as well as the 450. It is harder for me to fly in tight places.
I think the best analogy is that my Witespy 450 is like a Ford F-150 pickup truck; does everything, never breaks, cheap to fix, easy to repair, does the job. My Hoverthings HT-FPV is like having a race car in the garage that is fast, complicated, requires frequent repairs, is twitchy to drive hard, and prompts me to try things I have no business doing, usually producing a high speed video ending with a session of lawn darts and fade to black. They are worth every hour of the repair!