I much prefer
Claire. It is simple yet sophisticated, ages well and is a classic. Everyone has heard of it and maybe knows one or two but in the US anyway, I don't think it is overly popular.
I like it equally as a first or middle name. As a first name, I think it works better with a long middle.
Claire VictoriaClaire MargaretClaire ElizabethClaire MadelineClaire AnnabelleClaire MarieClaire Alexandria