Yes, I have, and I believe it's the ONLY affordable software to encode/burn Blu-ray Discs on a Mac. It can be limited (compared to say DVD Studio Pro) regarding menus, layout, etc, but it gives a basic set of tools to make discs that play on set-top Blu-ray players. It's a bit more like iDVD in respect of its flexibility.
BTW: note the "new" nomenclature used for Blu-ray Discs:
BD (not "BR") = Blue-ray Disc - commercially pressed
BD-R = write-once (like CD-R or DVD-R)
BD-RE = writable, erasable, then re-writable (like CD-RW or DVD-RW)
I only mention this as it can be confusing for those used to CD and DVD authoring/burning terminology.
DEFINITELY buy a couple of BD-RE discs for your first few experiments. BD-Rs are available in inkjet printable form if you want to go the whole hog with decent looking artwork on disc, and (the correct)
Blu-ray library cases. These cases have different insert sizes compared to DVD cases.