On the assumption that the pin type is not glued into the boom, the benefit there is that the boom slides right off the gooseneck when you are taking the rig down.  The strap types require you to undo the ring-ding (cotter pin or ring cotter) and remove the clevis pin to disengage the boom from the mast.  I think the strap types are more positive in that there is no chance for the boom to work back and forth, but that's not likely a real issue on a small boat like this with the sail hoisted.  I can see how, when you drop sail, the boom might slide off the pin, but I've never used one myself.  Of course that won't happen with the strap type.

The sliding gooseneck gives you the opportunity to rig a downhaul to adjust luff tenson on the main if you are the sort to worry about it.  It can help in brisk winds to adjust the draft on the main.  It does mean another string though (and probably a couple of blocks and a cleat).  You could do the same with a cunningham reef if you have the cringle for it on your sail, but that's more a big boat type of setup.

Great info Mummichog!  Thanks!  I was wondering if it had as much range of motion and if that would affect downind/by the lee points of sail.  Luckily, everything is in stock at Fisheries in Seattle, so I'm going to make a run down there to check it out.  I'll let you guys know.

I'm not crazy about the pin design for it's ability to pop out.  I guess I could rig some sort of parrel/snotter to keep it in place if needed.

I bought one of each, so I'll let you know.  The good news is that they have the same bolt pattern, so I can try both.  I'm going to wait until I've made the sail so I can use the luff to help determine the spacing on the mast.  The one with the pin doesn't have the built in shackle to attach to the tack.  The one with the two tangs has a pin to easily remove the boom from the mast.

I was able to get the 12' sail track locally, to save shipping, so I can cut it down to the right length.  It was the same price as the 8' that CLC sells.  I just paid for gas instead of shipping.  Seattle traffic is horrible, BTW...

The sail track stops are on the West Marine website for $80 each.  That seems a bit much.  You can use the less expensive ones without the fancy thumb screw, you just use your own stainless screw.

There's a large part of me that just wishes I had bought this stuff from CLC during their 4th of July sale...

Making the mast section as per John's instructions was pretty easy.  I used a router with an edge guide instead of a table saw to hollow out the middle of the halves and the gap for the sheave.  I think it'll be much more attractive than an aluminum pole (although I don't have the take-apart option).  I may try the aluminum version later on.  I will also probably make a cradle to hold the spars, oars and blades that mounts somehow in the boat, probably over the gunwales.

Oh, I forgot to add that they both swing about 15° forward of the beam on either side.

FYI, I decided to go with the one with the straps.  It has a built in shackle for the tack and is easily removable with a quick/fast pin.

Also, I got the fancy stop at West Marine.  The thumb screw is captive, so you can't lose it.  Nice feature, but still expensive.