Battery life
Maybe I simply don't read as much on my Kobo as you do, but I find the battery life amazing. I rarely charge it. As I type that, I realize that I read quite a bit of paperback books though.
cases
I'm not too picky about this. I use the navy blue Kobo case designed for the Clara. It's not the greatest thing in the world but I enjoy it.
All in all, I don't have much to compare it to other than a VERY old Kobo - like one of the originals I believe. It was incredibly slow and battery life on that one was horrid. Yeah, the screen was bigger than the Clara, but the Clara is leaps and bounds above that ugly thing I was using.>
Ah yes...I forgot about that as well. My current scale can switch to mL and I find that useful, although I don't know if it is actually calibrated any differently for mL vs. grams.