I have a Katherine, known as Kitty. I prefer the name spelt with a C, but I taught a Catherine known as Kate, when I was pregnant and she said the worst thing about her name was the C/K confusion. It was a nightmare and advised me not to do it. So I have a Katherine with a K.
She was the only Katherine / Kitty at her primary school and there is another Katherine in her year, but she is the only Kitty in her secondary school.
She likes her name, more so than my eldest who had a much more fashionable name. And she never gets comments that "my mum / aunt / gran is called that". I think because Katherine is more like Elizabeth - it's always there as a name, people of all ages are called it, rather than a Helen which is rather dated as name. There's also enough of them that she can occasionally find her name on pens / notelets etc, which pleases her :-)
The one thing that did annoy her was the Hello Kitty phase. For a while, people would always say it and buy her Hello Kitty things for her birthday. She doesn't like Hello Kitty, so that did annoy her. Thankfully that is out of fashion now.
We chose because we couldn't agree on a name, and it had a lot of nickname potential, but actually I really like it - it is a timeless classic.