I adore
Catriona and sometimes wish I had used it for my own dd,
Katherine.
BTW, I used to be on another naming forum and a friend of mine was from Edinburgh. She told me once that
Catriona is pronounced in such a way that nonScots hear '
Katrina,' however, it's actually pronounced like Kah-TREE-uh-nuh. She said the pronunciation is difficult to describe fully but the name actually has 3 1/5 syllables rather than four (the 'uh' is so very slight). Also, she said it's fairly common to hear '
Katrina' in Scotland.
I prefer Triona to
Riona but it's not bad at all.