The only cons we ran into (we didn't find out either time).
1) When the NIPT results came back, we couldn't open the email, we had to wait until our provider called us. You can opt out of the sex-based testing, but then you also wouldn't know about a problem with the sex chromosomes, so I wouldn't recommend that.
2) Clothes in general are fine, we prefer gender neutral stuff anyway, but it does make hand me downs a bit harder. You need to either take it all (what we did, figuring we wanted 3-4 kids anyway so someday we'd use whatever) or just opt to only take gender neutral stuff which, depending on your sources, can really narrow what you'll get.
3) You have to agree on names for both sexes. We actually had a big fight about girls names when I was pregnant with my first, and part of me was like "there's a chance this doesn't even matter" - we almost found out to avoid the fight. And we did turn out to have a boy, but #2 was a girl so we'd just have been putting off the inevitable, I think.
4) Basically every time we interacted with anyone (midwives, ultrasound tech, specialist, nurses) we'd lead with "we don't know the sex of the baby and we don't want to, hello!" which was mostly funny. Reminded me of this scene in Seinfeld -
https://www.youtube.com/watch?v=G4BxeSOem_0
Overall, those are pretty minor in the grand scheme of things. And there are MAJOR pros - announcing you're having a girl means that half the stuff you're going to get at your shower is going to be frilly pink completely impractical outfits. My cousin literally got 10 frilly pink dresses in baby sizes. And they were both finishing up grad school and just starting their careers and could have really used more of the practical stuff from their registry. What a waste.