lol, that's a bit of a mistake thar. Perhaps it's got an 8 foot flying speed ?

To chip in my opinion alongside Bhu's, It does seem underpowered compared to a certain other 'holy' class's mount, but then again, only up to third level. Great Fly-by Attack seems a little iffy.
It's a bit of a parabolic power curve, I'd say. But, since the mount doesn't stack with anything, that means that the strong bonus feat is balanced down, so...
I dunno.