i think Prince's years of his best creativity had 2 have been between 1985-1986. I mean the whole "Under the Cherry Moon" movie'Raspberry Beret video, songs like "Big Tall Wall,Joy In Repetition,Movie Star. Also there were tons of songs written between those periods

Others Here With Us
Sexual Suicide
Life Can Be So Nice
God Is Everywhere
Empty Room!!!!!
Rebirth of the Flesh

PRINCE AT HIS BEST!

Those are great songs and that period you mention was of course a very productive time for him but other fans would argue that 1982-1984 were even better, considering he wrote all the music and lyrics for all The Time albums, wrote most of Sheila E´s material ( killer songs such as Noon Rendezvous, A Love Bizarre, The Glamourous Life etc.) , The Family, some of the stuff on Vanity 6 and Apollonia 6, his own material like 1999, the b-sides and, of course, Purple Rain.

Personally , I prefer the material above to the period mentioned by you because there were a lot of songs planned for Dream Factory that I don´t dig that much, like Teacher Teacher, Make Somebody Happy etc.

But, that being said, don´t forget that Prince still came up ( and to this day still does come up ) with great music after those years, like a lot of the stuff on Diamonds and Pearls, o+>,The Gold Experience, The Truth, TRC and 3121...

It might be a bit overshadowed by Tony M but then again he released so much stuff that you could easily make at least ten immaculate, flawless albums from that material ..