I now have both the Pirate Cycles and Sportsman Flyer laid back seat posts and thought I would share my impressions.
Pirate Cycles
This seat post is heavy and solid. It uses a steel bar to offset the seat post. Essentially no mind was paid to asthetics as the bar is wide and unwieldy, but it functions well and allows you to set the seat back a lot farther and lower than the Sportsman Flyer model. You could go to town with a grinder and round off the edges to make it less obtrusive, but you'd be grinding a while as there is a lot of metal to lose... One functional drawback that I see is that the seat post is not very long and a heavy rider on the seat would transmit a lot of lateral force to a short section of seat tube which might cause some problems if the frame isn't up to it.
Sportsman Flyer
This post uses an extension at about 45 degrees to set back the seat. It is a lot less obtrusive that the Pirate Cycles model, but does not let you put the seat as low or as far back. The seat post is also a lot longer. While the seat is not as set back, the lateral forces generated are less and more spread out. One other drawback I noted was that the angled seat post allows the seat to rotate from side to side if you haven't tightened it a LOT.
Overall, I prefer the seating position of the Pirate Cycles version, but feel a lot less stress being put on my frame with the Sportsman Flyer post.
Pics below should help illustrate my points...