Best uses for Souls?

[Perogue]

I have not unlocked the 3 ???? tabs to the right yet but i have put a fair bit into the game in time. I have been saving my souls cause I don't know what I should be spending these on the shop or should I wait to unlock these. In your playtime, what are the boost you cannot get enough of no matter how far you are that I should get with these souls?

[fractalgem]

so far probably generator power, prestige exponent, ascension power, and to a lesser extent stardust, but I haven't unlocked supernovas yet.

[Dwane Dibbley]

Finished game without using them. Prestige exponent should be probably the best, but unless you buy souls, boost from free souls isnt even noticable. So you can just buy skins.