As many of us reply to many people in this thread to more or less the same question: it's more a question of feeling and preferences than of speed. All the new speedcubes are fine for sub-8 second solvers and for sup-minute solvers. The question is, what do you prefer? fast, controllable, blocky, smooth... If you don't know you will have to try several cubes until you know. If you can't try several cubes (you don't have friends that cube, don't go to comps...) you will have to try and see, if you don't like it, see what you don't like and search for some other cube that's different. There are tons of video reviews on Youtube that can help you take a decision. Worst case scenario you will end up with 2-3 cubes. I have more than 14
If you can tell us at least, which was your main, and what you liked / disliked of it maybe we can reduce the search for you.