Really lovely shot! The bokeh is pretty amazing, I know how lovely it works, I've got the same lens except I've got the L version To make it better I think you could turn back the aperture a bit, like 3.5 or something to make the frog a bit more sharper but still have the field of depth. Lovely shot tho!!!
I have already also the 100mm 2,8f L lens from Canon. It is much better, you don't need a tripod to use it properly I know it could be a bit sharper, but the thing with those creatures are, that they won't sit calm long I just hadn't enough time to experiment