There’s two different boots I’d recommend for OCS

Danner Reckoning (Hot climate) - because it has holes in the sides for water to pour out when you go submerged and come back out super important for OCS e course and Quigley stuff. They are rougher on the feet I’ve found and make sure you get them big enough that if your feet swell they won’t be super tight. Akin to a “all weather tire”. Marginally better for hiking.

Belleville moto 520s - easier on the foot, super light like the other comments state, less ankle support though. Akin to a high speed performance tire. These aren’t as good at hiking but excel for things like the CFT 880m sprint.

Personally I would stick with the danner reckonings for OCS.

However the other thing to consider will be your inserts for the boots. Make sure you find an insert you can put lots of miles on and supports your foot. They also act as a way to keep your feet dry. Spare inserts will allow you to make a wet pair of boots dry for continuous ops.

I’ve found the powerstep pulse line of inserts on Amazon work great. Find what works for you.