Boat trip to Delos and Mykonos from Paros

You can visit Delos from Naxos or Paros, day trips go via Mykonos where you'll stay for a few hours.

In Paros, contact Polos Tour:

https://polostoursparos.com/daily-cruises/

In Naxos, contact Zas Travel:

https://zastours.com/naxos-to-delos-mykonos-day-trips

Unless you're looking for a private excursion, all day trips are on the same boats, regardless of the agency you book with.

As for whether it's recommended, I'd say it's like any activity, whether cultural, sporting, or leisure:

If you're interested, I recommend it, but if you're not, why would you go to Delos? If, for example, you'd prefer to go to Antiparos for the day, go to Antiparos instead.

That excursion is a good one. Delos is a major archaeological site in Greece. The bonus is after visiting Delos the excursion boat continues on to Mykonos. You get an opportunity to visit Mykonos without having to pay for rather expensive accommodation.
We prefer to do this excursion on MV Alexander. Naxos Star can be way more bouncy if the seas are up.
Some images
Day trip Delos and Mykonos https://www.flickr.com/photos/stanbr54/albums/72157637922138466/

My daughter and I will be on Naxos at the end of June - high school graduation gift trip - and I booked this Delos-Mykonos tour on the MV Alexander ferry...have been second-guessing myself ever since about whether I should cancel it in favor of more relaxing on the beach but I think you've convinced me it will be worth it!

Good call. This is a very good excursion. Not particularly expensive so good value. Lots of interesting ruins at the site.