Moka-Tiger (Ron)
1646
I love the IWC and the Seiko.
I like IWC, both their watches and the brand. A very class, elegant, and classic look here. Thumbs up.
And, since your son is a young man, I think the Seiko would look great and might look appealing to a younger-generation wearer IMO.
You can't go wrong with any. And as a safeguard to not going wrong, you might ask him which one he likes.
In fact, you might enjoy going to try them on if that is possible.
Make the purchase a fun event for both him and you, as you are purchasing a beautiful watch for a special occaison.