Vests get more expensive everyday. As of this writing it 1 vests is 405 steem. Last week it was 300 something.
Back in the day it was 1 vest = 1 steem.
Therefore Vests get more expensive everyday. And I really think that it is vests that that effect your voting power more.
Vests DON'T have interest. You only earn vests through posting and curating.
AND WOW! I think I was a month too late in joining when it was 1 vest per Steem. wahhhh! :( I'm even noticing the higher our reputation score goes, the harder it is to get to the next level. Kind of feels like a hamster wheel sometimes! LOLYes, thank you @mctiller. I probably should have included the fact that vests do not get interest, but I was afraid their hair might catch fire. There is so much to learn and a steep learning curve for newbie bloggers and anyone, like me, who's never had to deal with cryptocurrency until now.
You're correct about the rep. Getting from 60 to 70 is harder than going from 50 to 60.
And I'm still not sure if I understand Steem Power, but I really think it's the number of vests you have that is the important number.