One thing that I discovered with the mid-boom sheeting on my a-cat is that it allows you to trap out fully extended even when sheeting hard. If you watch your crew sheet from the wire while in the middle of the boat, they have to lean way forward or go starfish to counteract the sheet forces trying to pull them back. It's also easier to maintain your footing with the main pulling you straight in on the boat.

My a-cat has both mid-boom and mid-trampoline sheeting...that is I have the option of grabbing the mainsheet at a block in the middle of the trampoline or at a block in the middle of the boom. I like the angle to the trampoline but it feels spongy...and I ask myself why have an $80 non-stretch mainsheet if you're sheeting point is the middle of the trampoline?