So I don't already own a PB beanbag chair, but I researched them here & on other boards. They generally get good reviews and the 1 downside is what you identified: the price. I ended up going in a different direction since in the end for us, aesthetics weren't super important, and we really just needed a lightweight, occasional use chair for TV watching in the basement (I got the Big Joe Milano, which we like so far, but it's only been a week). But, since your DD is really into sloths, and you said she even researched her own sloth chairs, I say get it!
Jen, mom to "Little Miss Tiny" 4/07