City Pass for Copenhagen - advantages or disadvantages?

you can read more about the city pass here. https://dinoffentligetransport.dk/citypass
What exactly are you unsure of?

If three full days, and going out of town west (Roskilde) and north, then yes, get the card, it's worth it.

Used to be the klippekort was not available to non-residents but maybe that's changed.

Just also raising the Copenhagen Card. This one is more expensive, but in addition to free public transportation throughout Zealand, it also provides free admission to the majority of the attractions in Copenhagen and its environs. It isn't worth if, in my opinion, for the free admission alone. But if you plan on traveling at all to Roskilde, Helsingor, etc., outside of Copenhagen proper, then I think it is worth consideration.

Tom, the City Pass is only valid for the city, not for trips to Helsingør or Roskilde. You will need the Copenhagen Card for that. And the paper Klippekort has been discontinued a few years ago.
But the advantages or disadvantages the OP asks for depends on where the OP actually plans on going. @rmgrove can you tell us more about that?

I didn't know that there were 2 passes, but side trips out of the city are recommended, even for a short visit.

I was there in December, and bought a 7 day Copenhagen Card at the airport after arrival.
It entitled me to get the train into the city from the airport, be able to jump on and off local trains and buses at will.
(Great if you get tired, or just want to ride around and see a different neighbourhood).
I got into numerous museums and exhibits with it, and got a discount at museums that didn't accept the card for a full ticket.
I also took the trains to Roskilde and Helsingor, and then the train back to the airport at the end.
It wasn't cheap, but for the sheer convenience of it: it was well worth it!
Highly recommended.
Plus, it saves you looking for change and buying single tickets every time you want to take a bus.
The transport system in Copenhagen is fantastic, and so easy to navigate.

I want to thank everyone who responded to my questions about the city pass. I appreciate the comments concerning the Copenhagen Card - although a bit more expensive, it sounds like it would be worth it since it includes admission into the major sights and transportation. It sounds like it also includes train transportation to nearby cities, such as Roskilde & Helsingor. Does it have to be purchased online, or can we pick up the Copenhagen Card when we arrive? Thanks. Rose Mary

You can buy it when you are in the city. The website lists all of the sale locations (https://copenhagencard.com/sales-points). They are all over the city (and at the airport). Note that you buy it for a set number of days (so you'd probably want to consider the 48 hour or 72 hour card). But the clock doesn't start running until you first use the card.

At the airport worked for us, and the person at the TI knows how to get American credit cards to work-- not a given in Denmark. The Copenhagen Card also frees up staying right in the center and staying out a bit where it is much cheaper, both lodging and restaurants, since any transportation is covered and what's a 10 minute train ride?