manual slider you mentioned gets enabled in steemit after 500SP? is that true?

Yes, and that is the only thing that changes. No other interface changes when you get it. If you have difficulty using the manual slider on steemworld, I do have an old post on how to use it, but steemchiller is always updating his work, trying to keep it current and updated, so things may have changed on it.

I don't use steemnow very often but is good for a quick overview.
Steemd used to get used by me quite frequently, but you have to reload it to get the current info.
As for busy.org, well I did join, but found the front end to be...well busy. Busy and a lot of the other blockchain interfaces are like the old internet browser wars of the early days, AOL, Compuserve, Genie, days, before Mozilla browser. So it is just a personal taste thing. However that being said, they do have a vote slider.

As of @steamchiller's https://steemworld.org/ it truly feels like is one of those Pro Tools that the big guys in the Steem world use. Love the dashboard feel!

It is by far one of the most professional tools available for seeing information on your account. Followers by, date. Mentions by type, (very similar to gina bot), and several other tools, with the initial "Stats" page working and looking very professionally in my opinion.

Glad I was able to be of a little help.