Struggling to decide between the two. Those of you who have had experience with them, are there any pros/cons?

From what I've read, globemaster has bigger blooms, but is a lighter color purple. Purple sensation is darker with smaller blooms.

A few questions remain:

1.) Are they equally as dense? I love the pictures of globemaster that show them as a big dense puff-ball. Some of the p.sensation pics make it seem airier...

2.) Is purple sensation shorter?

3.) And most importantly... (because if I can't decide I think I'll just mix them which might be nice to have a variety of sizes/shades of purple in the border anyway) Do they bloom at the same time? I don't want one to die out faster than the other leaving me having to cut down 1/2 the blooms and making the border less full. I'd rather have a 'big bang' and have it be done :)

Thanks for your help and experience---this newbie appreciates it!