I recently got the PRG (amazes me how blogs do not push the 50K sign-up bonus for 2K spend, I guess they get no kick backs) and I do not yet have the AMEX Plat. I have within the last year canceled both the personal Delta Gold and Delta Plat after the first renewal year AFs posted. Gold of course is waived first full year, and Plat I paid first full year right after getting it (but you get the companion pass after 12 months and they do not claw it back, even if you cancel after 1 year and get the 2nd annual fee refunded).
Anyways, I am getting ready to keep my personal SPG card after the first 12 months being fee-free and pay the AF on it. I am a ways out from the first fee I'd have to pay on the PRG card, but I suspect I'll keep it and pay the fee for at least one year, to offset any potential issues from closing the Delta Gold and Plat after the first year. I'd probably be okay regardless since I kept those cards technically more than 12 months, but I quite like AMEX and do not want to chance my long, positive history with them for something short sighted.
I do have the Chase Sapphire Reserve which gets basically all my travel and dining spend, and airline tickets for the trip insurance, yet even despite this, paying 1 fee for the PRG in the 2nd year I think is not the end of the world. Especially if you got the 50K sign up bonus, versus the 25K one.