To stay in Naples or Sorrento?

I would stay in Sorrento for seeing the Amalfi Coast. But if you have an early flight, I would stay in Naples for your last night. On the way back to Naples, you could see Pompeii.

What's your comfort with bustling cities? I loved Naples from the brief day trip I did and wished I had stayed there instead of Sorrento, which I found too touristy. But I like cities and am used to urban life. Some people would find staying in Naples intimidating. Sorrento is certainly much more laid back and comfortable for the average tourist than Naples.

You say you want to see...MAYBE SOME of Naples. You should see it but do not stay there if you aren't interested in experiencing the city itself, history, archeology, chaotic urban setting. We stayed in both Naples to see Naples, loved it, , and Sorrento, to see it and to easily access Pompeii, and the Amalfi Coast.There is a d dedicated bus from Naples airport to Sorrento or get a private driver. If you stay in Naples, take Circumvesuviana train to Sorrento, a commuter train. I wouldn't take it with luggage.

What time of year? What is medium price to you? In Sorrento in season, my guess is that medium price range is over €150/night, maybe closer to €200 on weekends.

Can you reasonably get from Sorrento to NAP 2-3 hours before your flight out, allowing for traffic delays or do you need to spend your last night in Naples?

I am a very experienced traveler and grew up in Chicago. Big cities don’t faze me. However, of all the places I’ve been, I hated Naples and couldn’t wait to leave. Sorrento would be my choice. I would go up to Naples the afternoon before the departure, visit the Archaeological Museum, have a nice dinner, and sleep in a hotel there. Look on booking.com for hotels and prices.

I hated Naples and couldn’t wait to leave

I think it helps if someone offers at least some additional explanation/ description to help other posters, not just says they hated something full stop. (Obviously I'm not in the "hate Naples" camp. I really enjoyed it because it was an unapologetically authentic city that wasn't revolving around tourists. I loved the lack of tourists actually).

One factor as stated is whether you want to stay in a large city or a resort area.
Another factor to consider is what time your departure flight is (and arrival for that matter--as some people visit Pompeii in transit).
There are multiple trade-offs for any location, especially in regards to transport, and knowing what month is important too (for example in less appealing weather I would want to be in Naples for sure).

I loved Naples on my all too brief day-trips from Sorrento. But I have to say, the constant assault on your senses (and the Circumvesuviana) can take its toll and I was glad I could counterbalance it with a relaxing evening in Sorrento. Naples might be the only place where a real spurge on a nice hotel, a quiet refuge, would be worth the money. Pompeii is about as easy from Naples as Sorrento is, but Amalfi Coast is not.

The one thing Sorrento really has going for it is options. Three nights isn’t a ton of time, but from Sorrento all sights/destinations are achievable and there are multiple ways to get to them. So, quick answer: Sorrento.

Such different places ; we can give our opinion but you really should read the pluses and minuses of each and decide what is right for you.
I am not at the point in my vacation travel interests (which continue to evolve) ; where I seek out gritty cities as a place to stay so my decision of Sorrento would be an easy call for me.
Other people love Naples and may find Sorrento and much of the Amalfi Coast too touristy for them.

Naples is "smack you in the face" Italy. It's not for everyone. One of Harold's favorite quotes about her is "there's nothing subtle about Naples except her charm." It's not dirty or unsafe, it's just kind of unkempt.