I love the name Bess. It has an Old World feel, and sounds simple and sweet. I considered it for one of my daughters, but didn't want mean kids mooing at her or calling her "Messy Bessy." It is an adorable name though, and I hope it comes back into fashion. I ended up naming my girl Ellie instead.
I'm an Elizabeth who has used different diminutives at different stages of my life - I was "Libby" as a little girl, "Ellie" in high school and "Eliza" in college. My husband started calling me "Beth", which I've been for the last twenty years. I'm planning on using "Bess" when I get to the grandma stage - it seems like a good grandma name.
I think Bess has a lot of potential for from old-world memories and charm into some modern-world soil, so to speak. Betty is quite darling as well (which is also what my Grandmother goes by to friends).
My parents picked this name for me out of a book. As a kid I hated it. I like it now, in my 30's. I was teased in school as "Bessie the cow" even though I wasn't fat. I like having a short name that is easy to spell. A lot of people hear Beth, no matter how much I pronounce the ss at the end.
It is nicknamey and also dated in my opinion. I can imagine an old, sad aunt named Bess.