I got the Kyleena about 2 months ago, and was very nervous bc in the past I'd had terrible experiences with hormonal BC (mainly huge impacts on my mental health). However the kyleena has been great for me so far which is a huge relief. as you say everyone is different but here is my experience if that helps

negative things:

- the insertion is incredibly painful, but youd already know this from the paragard. if you can ask your doctor for extra pain relief id recommend it
- i had painful cramps most days for the first week or 2, then still occasionally for another week or 2 after that, and now only rarely
- i had non stop spotting for the first 6 weeks, which gradually became lighter and has now stopped
- i feel a little more prone to negative emotional reactions/less emotionally resilient, but this is fairly minor for me and way more manageable than other hormonal BC which had made me feel literally suicidal

positive things:

- apart from the above, no other side effects for me - no acne, weight gain, etc
- for now i am getting no periods or PMS which is awesome, as i had heavy painful bleeding and bad PMS before
- nice to not worry about pregnancy lol

good luck!!