Pretty cool. I'd probably use it since it looks to be pretty beneficial for brainstorming vacations and getting a quick and rough idea for how many miles would be needed to certain places. The biggest limiting factor I can see is that redemption rates change based on when you fly, and that doesn't show up on this site.

I do especially like that it has distances for different routes quickly listed there. I haven't seen that on a website before and could see myself using that when calculating how many miles I can expect for trips.