I think it's fine. Because the phone is already big, the extra "hump" is not too hard to get used to.
I got a metal bumper case to work with the extended battery. I posted a picture in the other thread for 5200mah battery. If you drop it, it will still come apart most of the time.
I did use a cheap TPU case and cut out a hole for the hump and that works out fine as well. This will keep the phone together better if you drop it, but it was a really cheap TPU case, so I ditched it eventually for the bumper, which looked alot slicker.