All are fine plants - Salome and Splish Splash not as robust as some. IMO, Ballerina is one of the finest of the hardy geraniums, pretty much a nonstop bloomer in my garden and about the best of the cinereums, surpassed only by its cousin, Lawrence Flatman. If you can find 'Larry', I'd recommend him first :-)

Buxton's Variety is a standard in the blues - a clear sky blue with a white eye. It is one of the parents of Rozanne and is similar enough that it is difficult to them apart at a glance - Rozanne offers a heavier and far longer bloom, so I'd opt for her over the older form.