Kyoto-Tokyo-Osaka is the JR pass best?

I will be in Japan for 11 days in March and while planning itinerary I can�Lt see if the 7 days JR pass is the best. I want to travel by train from Kansai to Kyoto, stay 3 nights, from Kyoto to Tokyo, stay 3 nights, Tokyo to Osaka , stay 4 nights while taking day trips to Nara, Kobe or Himeji. Should I buy the 7 day JR pass or would the single tickets be the same?

Yes, a 7-day Japan Rail Pass pays off for a shinkansen round trip between Tokyo and Kyoto/Osaka, if completed within 7 days.

yes, it's really good, you can use it for the fast train tokyo-kyoto-osaka.... and also for any other JR train and JR lines underground in Tokyo. Not only saves you cash but time. you can use it as it is not need to exchange for tickets. If you wish to book a sit in the fast train, you need to reserve, but if you don't want to, or not sure the our you want to trabel, no prob, just be a bit earlier at the station and get into the non asignated seat wagons ( about 5 wagons ), and just get any sit, when I went there, this november, it was no problem at all. they run frequently, so even if you don't get sit in one you can take the next as you be the first in line, and japaness do the most respectfull lines.
Just make sure you buy the ticket in your country as the pass can no be bought in Japan.

you can use it for the fast train tokyo-kyoto-osaka.... and also for any other JR train and JR lines underground in Tokyo.

Just note that apart from short sections of the Keiyo and Sobu/Yokosuka Lines, there are almost no underground JR trains in Tokyo. And that the Japan Rail Pass is not valid on Tokyo's subways.