I've been using the Merlin a bunch with the 5DII (and now 5DIII) and it's a superb product, but I'm struggling to get the control I really want from it. The problem, largely, seems to be inertia, and preventing side-to-side sway. There's no doubt that operator skill plays a huge part, but I've definitely plateaud in my ability to improve with it, and I practice a lot. So I'm considering a few different options. The obvious one is to upgrade to the Pilot - I can use my Merlin arm and vest by replacing the arm post, and the addition of the monitor and battery (even if I don't want to use it) will help the inertia question, as will the post length. Alternatively I could stick with the merlin and try adding stuff onto the camera to bulk up the weight, and have more counterbalance weights in play to keep it all more stable. I could also practice more. I'd love to hear from anyone who's gone from the Merlin to the Pilot (or even to the Flyer or Zephyr) and what your experiences were. I'd prefer not to hear from anyone who's going to try to sell me on Glidecam. Been there, tried that, if it works for you great, but it's not for me!