This lens is much better suited for landscape photography. If you are looking for a good all around portrait lens, I would go for the 24-70 f2.8. The lenses you are describing above would have to be used literally right up in the subjects face to fill the frame so unless you like cropping in post and have the MP to do it, I think a better choice would be the 24-70.
If you are after a prime for portraits, the minimum focal length for all around use would be 50mm. Personally, I prefer an 85mm. It is my belief that the closer one gets to the subject, the more "posed" the subject gets because the camera is all up in their face and they feel like they have to perform for the camera. I like candids, especially of my family members. BTW, f2.8 is a fast tele-lens and will do nicely in indoor low light. Of course it will be wonderful outdoors too.
Of the Holy Trinity, my first was the 24-70mm and is still my most used and most beloved lens.
NOTE: My comments are based on the assumption you sport a FX camera. If you are using a crop sensor camera then the focal lengths of all the lenses above are multiplied by 1.5 times (ex. 50mm = 75mm on a crop sensor camera). My choices would change slightly if I knew were running a crop sensor.
So many options .I get confused easily .Ill have something on monday .Ill end up going to the camera shop and trying different lens i speak of in a real situation.
Depending on the size of your camera shop, they may rent lenses. If not, there are places online that do. Perhaps you should try them out before you buy since the lenses you are discussing are huge dollars.
I can try them out in the camera shop i buy from .Ive got good relations with them .Ill take them for a few days and use them ,take back what i dont want .I know the owner of the shop .it works out well for me .
Cant be any worse then me buying my 800mm lol.
The lens i talk about ,he has them for rent also .so it works out good.I dont get charged a thing though.Untill i buy .Heck i can even get a glass from him pay ltr date.They have been good to me .Ive spent thousands there with them in the past few yrs .Good ole southern folks