There are likely some differences in how the cultures are formulated - particularly if it is a blend, the proportions may be different. But I would say you could use any of them with good results. I mostly use Danisco, just because that is what I can most easily get; the main exception is Flora Danica (by Hansen? I think), which I use fairly often.
A highly recommended resource: Giancalis Caldwell, Mastering Artisan Cheesemaking - tons of helpful information, including the various types of bacteria and yeasts and such, and which are contained in various brands.