Choosing DIS was probably one of the best decisions I've ever made. The program has been around for over 50 years and during that time they have definitely figured out how to iron out all of the small details to make all 900 students' experiences good ones. While I was listening to my friends in other countries panic about finding an apartment and dealing with setting up wifi in new places and struggling to get around, I was comfortably sitting in my new kollegium where everything, from transportation passes to lists of places with student discounts was provided for me.
Because there are so many Americans in the program, it is usually easy to make friends, especially if you participate in their excursions to places like Hamlet's Castle early in the program (sign up for them early! they fill up fast!) and in classes. It is also possible to take classes at Copenhagen University, where you can also make Danish and other international friends. People especially make close friends in their core classes, because of the 2 trips that are taken with the class.
Overall, DIS provides an excellent balance of making sure everything is very planned and organized without making you feel over-programmed or like you are not deciding on your own what you want to do. They provide many options for planned things (trips during the 2 week break, long weekend excursions, wine tastings, trips to IKEA) but if you are a person who'd rather be more independent then it's easy to find your own things to do as well without going through DIS.
Copenhagen as a city was also extremely welcoming. I always felt safe, even when I was taking the 3am night bus back to my kollegium from the bars downtown. It is an easy city to get around, especially because DIS gives everyone a transportation pass. There are lots of neighborhoods to explore and the city has a lot of interesting history. You can also rent/buy a bike to join the millions of Danes who bike around their city daily. (I highly recommend this! So much fun!) People have a reputation for seeming cold and distanced on the street (Danes generally don't make eye contact or small talk on the street/bus etc) but if you directly approach someone when you need help or directions most people are sweet and helpful. Learning and noting cultural differences was so interesting, and there are many aspects of Danish culture, like prioritizing family relationships, biking, and hygge, that I have brought back into my life in the US.
Some drawbacks that people mentioned when I was there: sometimes people are placed in housing that is a long-ish commute from classes which can be a pain when trying to hang out with friends later. The language is also kind of difficult to learn, but basically all Danes speak English, which is a pro and a con, because I found it hard to try to practice my Danish in restaurants etc because people would rather just speak English than listening to you try Danish, and Copenhagen is one of the most expensive cities in the world. Going into it, I was extremely worried about money and getting used to seeing prices in dkk was very difficult. $1-about 5dkk, so every single price you see is enormous. But, I just got really used to cooking my own food and figuring out who has lunch specials and DIS student discounts. It is definitely possible to manage in Copenhagen without draining your bank account, but it is a challenge.
Overall, I absolutely loved my time in Copenhagen and I would do it again in a heartbeat if I had the chance.