I used to own a sniper and just got a magnum. I have only had the opportunity to creek the Magnum a few times as of yet. My views on the outfitting are as follows:
First I am 155#'s and 5'8".
I had to experiment with the seat placement for a while but it seems that for my height and weight about 1 inch from all the way forward provides the best front to back balance. Any farther back and the bow seemed to ride up a bit more than I liked and the stern chine would get me a little squirrely. Having said that with the seat moved forward it is super stable and and very predictable.
I took out the hip pads and glued in foam pads. For me this seems to work better as I can have the hip pads up higher and over my hips.
I really like the back band as you can move it up or down on your back about 3 inches. I have it all the way up which keeps me forward (more in the drivers seat) and helps keep my upper body from getting back past my hips during strokes. Also it seems to provide plenty of back support and is comfortable.
My first impression was that the thigh braces didn't provide enough support, however after moving the seat forward and glueing in foam hip pads they seem to work well. I think I just needed more hip support and to get my knees up higher. Also, I glued in knee blocks which helped alot. Additionally, they make it very easy to get into and out of the boat.
Overall with the following adjustments it is pretty responsive and cush outfitting.
First, I would say that I really liked the Sniper. It is super manueverable, boofs about as easy as it gets, is very stable and predictable and resurfaces after drops very much undercontrol. However, it does have a tendancy to get pushed around in higher water flows unless you are aggressively paddling and leaning forward. Additionally, it definately isn't the fastest down river boat. Having said that I had it in California for three weeks this year during the high water/flood event and it performed well for such a short round boat.
The Magnum seems to be alot of what I liked about the Sniper with the addition of more speed and a bow that always stays on top of the water (which I feel is important). The bow rides high and just seems to ride right over holes. Additionally, the water just seems to push the stern through the hole. In other words I think that I will be feeling much more confident in the Magnum when it comes to needing to plug a hole.
The Magnum also is very crisp when peeling into and out of an eddy and is quick to accelerate. As far as boofing it seems very easy. I need more time in it in this regard as it is much faster than the sniper and my timing seems to be a little off (I found in the Sniper I needed to wait just a split second longer before the stroke).
I have only had the opportunity to paddle it a few times (with many more to come), but those are my initial impressions. Overall I am really stoked on it. Hopefully this helps.