As an owner of two Omega watches (a Planet Ocean and Seamaster) I think my Seiko Monster is built just as well and seems to be more durable. It looks much less worn after years of use compared to my Omega's. It does have a less sophisticated movement but it's reliable and just as accurate. If anything my Omega's are running a bit fast.
That being said I just picked up a Seiko SNZG13 that I can use my Nato straps on
Seiko Men's SNZG13 Seiko 5 Automatic Black Dial Stainless-Steel Bracelet Watch
https://www.amazon.com/dp/B006ITF2H8..._I7BYxbB2ZNJQR
Also been really tempted to get a Seiko Shinobu Ishigaki Cocktail Time since all my other watches are divers.
Seiko MECHANICAL x Shinobu Ishigaki SARB065 Mens Wrist Watch
https://www.amazon.com/dp/B0038OLUMM..._F9BYxbWJ4NG4S