As I understand it, STEEM Dollars are pegged to the U.S. Dollar (even though an exchange may trade them for more or less than a U.S. dollar) and STEEM is the floating crypto currency you can trade through exchanges. STEEM Dollars held in your account earn 10% yearly interest. However, as shown in my article above, STEEM Power has even greater rewards.
Here is an article talking about the 10% yearly interest on STEEM Dollars: [Remember, Steem Dollars provide 10% annual interest tell your investor friends
I typically change my STEEM Dollars into STEEM. A one week process. Then STEEM into STEEM Power for the greatest rewards. STEEM Power also gives you VESTS which translate into voting power.
If you are powering down or need ready cash then you should hold STEEM Dollars.
Steem on,
Mike
from now on it's steem power only for me
It all depends on your situation. But you cannot go wrong on SteemIt when you set your mind to increasing your STEEM Power.
Have a great weekend!
Steem on,
Mike