Both are gorgeous - however - the bigger one is slightly more edgy ... It has that "I'm wearing my husband's watch and don't care that's it not dainty" feel to it. The smaller is a safer bet and is more classically feminine. My vote is the smaller if this is going to be a staple in your collection. If you already own a smaller watch, then the large BB is a fun, whimsical option. My $0.02.
I'm looking at yours pics again on my computer instead of my iPhone and I'm going to go ahead and say that I like the bigger one better. It's not dainty - but, it's more in spirit of why people buy a BB - it's fun and gorgeous. Do it. I'm glad you're getting the full roman numeral face ... I definitely prefer that as well.