Ffion is an old favorite of mine. I also think the meaning is lovely. It's such an unusual flower to be named after, but there were some foxgloves growing wild not far from where I live just last month and they were stunning. Plus it's nice to have a change from the typical
Rose,
Lily,
Violet flower names. I suppose it doesn't hurt that I love the Welsh language. I think the double f is interesting and at the same time not a huge obstacle.
Ffion is really pretty easily pronounceable. I think anyone who wasn't familiar with Welsh would say it just the way it sounds with a quizzical look.