I have not personally shot mechanicals because I am old school and don't believe in them. However, my Dad has shot several different models and this is what I think.
If you are going to shoot the traditional over the top mechanical I would use a high poundage bow (min 65-70) that shoots pretty fast (280 fps +). The problem you are going to run into with traditional mechanicals is pass through. If you are shooting low pounds and/or a slower fps the arrow may not pass through. Since the entrance hole is so small and no exit, the blood trail will be next to nothing.
Recently my Dad started shooting the Rage and even I was impressed. He is shooting at 59# with an arrow speed of around 250-260 fps. He shot a doe a few weeks ago and the arrow passed through. What impressed me was, even if the arrow didnt pass through the entrance wound was 2". There was blood at the site of impact. I don't get that with my fixed blade broadheads.
Mechanicals take alot of the tuning problems out of the equation. Makes shooting simpilar. Now that I have seen the rage in action, even I am thinking about giving them a try.