I have one, and we love it. It works great for those times when a wood fire is not allowed or when wood is just inconvenient. The 15" size is not a problem, and once the lava rock gets hot, it puts out an amazing amount of heat. I modified mine by changing out the fold-out legs; made new ones out of the same 1/4" rod but longer, so it now sits about 10" off the ground instead of 4".
While it isn't big enough for a very large group, it does suffice for 6-8 people. We've even used it at a friend's house for a party by just setting it in their built-in outdoor fire pit; 8-12 people around it, no problem.
Got mine at Amazon for $80, free shipping.
Here's the link