What makes you say, spheres are better. I gather that there are several variations, not just cubes and spheres.
I think they have spare clones of the queen, but only one in control at any given time.
The borg are one of the strongest/most interesting species introduced in the show. But what I don't like is the first time they were seen (in TNG) they were bad dudes. Federation ships got smacked silly. Now in the season premiere/finale episodes, voyager took on some borg tactical ship and beat'em down. What's the deal with this mentality that if the crew is sufficiently determined, they can overpower a borg ship. WTF!