USC Optic Opinion

I have been looking at optics for my USC, I was looking at the Trijicon Reflex and EOTech sights, which are both very high quality and very expensive. I then came across Sightmark, which were much less, but didn't seem like junk. So my question to you is, should I spend the money for the Trijicon/EOTech or would the Sightmark be a good choice and use the extra money for necessities like ammo? I have no experience with Sightmark, and don't want to end up with a sight that is useless, as some of my friends have done with cheap red dots sights (I mean really cheap $30-$50). Thank you for any replies.