Re: 2 scopes, which one would better suit my need?
I like Burris and Nikon. As far as power range, the 3x will outshine the 4.5 from 0 to 100 yards. Especialy on moving game. The 3x will also be brighter.
For long range, 9x is plenty out to 500. Once you start shooting long range, you will see how simple it is to shoot to 500. You may then want more power to stretch things further.
For an all around scope, I recomend the Nikon Buckmaster 4.5-14 side focus. This scope has a lot of potential, you'll grow to apreciate. $250.
For your 223 the Burris 3-9 ballistic plex will allow you to shoot to 500 without turning a knob.
I like them both, but would go with the Nikon.