I just bought a DD M4A1 and would like to know what red dot you guys think would go well? This is my flagship gun so I don't want a basic SIg Romeo. Looking at something like an Aimpoint Duty RDS or a HOLOSUN AEMS REFLEX SIGHT. Someone was telling me I want a site that sits higher on my rail, is that true and why? May even go with an Eotech is money permits. Thanks!