Short answer to your questions...
Yes, for me, it was worth the $100 I paid for it (no stone or peel included at that price).
It looks pretty cool
and the design makes it pretty easy to get the pizza in and out.
For me, the biggest challenge was to get enough heat to cook the top of the pizza at the same rate as the bottom. My most recent cook with the Kettle Pizza, I wrapped a cooking grate with HD aluminum foil and placed it on top of the attachment and then put the lid on. This simple mod made a huge difference and is close as I have come to getting them perfectly cooked.
I use a 1/4" piece of steel, instead of a stone. The steel was less than $20 and was on my way to work
I would try a kiln shelf, but can't get one local to me. The steel works awesome btw.