Steem Power is better because you get shares in Steemit called VESTS. Right now you can see your VESTS at https://steemd.com! You also get more bandwidth so you can do more things on the site. But it's mainly that you have more influence and can decide what should be seen more on the platform. You become more invested. Very nice if you like to be in a responsible position!

Also how your upvotes become worth more and that you get a slider to fine tune the reward you want to give out. I have more faith right now in Steem because I have more control over the return on investment. I see a return instantly. But I believe that ETH has a mega bright future as well. But that SP is worth so much you can really feel when you level up how it's impossible to ever wanna go back down again haha. Also brings me so much faith when I see how much Steemit is growing and the amazing plans the CEO over Steemit has when it comes to the next 5 years! He is so smart.