Reddots belong on ARs. Especially if you expect to do any close combat shooting.
Red dots of various quality are readily available from sub $50 to over $1k. Find a few in your price range post em here and We'll help you pick whats best for you.
PS those burris sights that skadoosh mentioned look nice. I just hate how everything has the integrated riser for an AR nowadays... Sometimes people want optics like that on OTHER GUNS!