I'm sure your editor will be fantastic.
Since Steemit.com made access to my wallet more difficult, I switched to using Steemworld.org to access my wallet and it works flawlessly with Keychain. Thank-you so much for that feature!
I also tried using the Internal Market through Steemworld and I think it is actually slightly more intuitive to use than the one from the wallet link.
I WAS, however, confused by the POWER-UP feature and its slider. I needed to keep some liquid steem available for my contest prize, so I typed in a value rather than use the slider. The slider value did NOT move to reflect the value I typed in. So now I have no way to know WHICH of the 2 values would be executed. As an experiment, I moved the slider to see what happens and it caused the numeric value to change. I then left the slider at the position that was CLOSE to the numeric value I wanted and then altered the numeric value by typing in a new value. The numeric value ended up being the one that was executed and not the slider value. Perhaps you could make that function easier to understand?
I have one thought that you may wish to consider: How do you feel about making the beneficiary of the editor optional? I ask this because I know how difficult it is for small accounts to see any growth at all and losing 10% might make it so that the smaller accounts will either not be using it and miss out or worse, quite Steem altogether. Those who have large incomes can afford to have 10% stripped off and will be providing the largest amounts to you anyway. 10% of tiny accounts will not be worth much anyway, so you would not be losing much.
Another thought would be to use some sort of threshold such as post payouts of greater than $5 would have the beneficiary fee taken, while posts earning less than $5 would not. The $5 threshold is just an example/suggestion. If you decide to implement this idea, I think it would be good to make it obvious to everyone what that threshold amount is.
Thanks again for all your fantastic work!