Just a bit of general advice ... they fall into two camps, fixed and foldable. The fixed ones are a fair old size, so need to bear that in mind depending on where it's going to be kept when not in use. I was given mine FOC by a dealership (when they gave up storing R129 hardtops for customers over the summer), so no idea what brand it is! But it's pretty substantial and solid (not a folding one).
As an alternative you can get padded hardtop bags that hang onto wall hooks (e.g. in the garage). I actually use one of those for protection, when the top is on the stand.