Well, we won't have Prince Herman to kick around any more, with his campaign ending on Saturday. It sure was fun while it lasted, though.
As far as the effects of his demise on the nomination contest, I think it depends on which of two views is correct. Some people see a GOP that is dominated by a strong anti-Romney group, a group that makes up as much as 75% of the party. If that's the case...well, if it's really close to 75%, then Romney has no chance and it doesn't matter that Cain is out. If it's in the neighborhood of 50%, however, then Romney's only path to the nomination is that the anti-Romney vote splits, and removing Cain makes that less likely. That's the logic everyone is using who says that Cain's demise helps Newt Gingrich.
However, if the real dedicated anti-Romney group is much smaller, which is how I read it, then the situation is different. As far as Romney vs. Gingrich is concerned, the problem for Mitt is that Gingrich should be fairly easily destroyed with a negative campaign, but going negative in a multicandidate race is tricky -- voters could easily wind up turning against both the target and the attacker. So what Romney wants is to narrow the field down, eliminating each of those who could benefit from that effect. And each candidate who self-immolates is a plus because Romney gets closer to one-on-one without becoming the bad guy.
(If that's true, Romney also needs Republicans to be immune from the charms of Ron Paul, who probably isn't going anywhere -- in other words, Romney's best realistic case after New Hampshire is three left standing, with Paul's support capped at a relatively small sliver of the party).
Now, in the event, whether Cain actually stayed or not didn't much matter because his support was already on its way to being completely gone, and perhaps it was unlikely at this point that he could have ever revived no matter what. But the real question here is whether winnowing the field rapidly is good for Romney -- as I see it -- or bad for him. If the ideal hope for Romney is that he can narrow it to one-on-one plus Paul, and then benefit from a tide of endorsements and positive coverage in the partisan press, then he's one step closer than he was a month ago.