Kick Port Bass Drum Insert Booster Black

I wanted to try one of these after seeing several reviews online claiming that the addition of low end to a bass drum is considerable. To be completely honest, whilst there may be a slight difference in sound, the benefits are far too subtle to justify the price.
I found the port very inconvenient to install, and that it tends to move around within the hole in the head if this hole is not cut to exactly the right size.
I tried the port with several different tunings, and different amounts of muffling in the bass drum, and found that there was little to no noticeable affect on the sound.
More of a gimmick than actually useful in my opinion.