Hi Bob. Welcome to the forum. I have another discontinued S&W Semi-auto that is very similar. Mine is the 4566. It has a 4 1/4"bbl. The 4506 has a slightly longer barrel at 5". As has been mentioned above, this model is a traditional DA, and nothing about it is 1911ish.
I would first ask you, what purpose will this gun fill? Occassional target practice at the rang? Home defense? Possible CCW?
I ask this because it is a heavy gun. Mine is a bit lighter than the 4506, and I wouldn't consider carrying it on a regular basis. It only has an 8 rd. mag. capacity, and I am also not a big fan of slide mounted thumb safeties. They are in the way when racking the slide, and the S&W thumb safety on this model works opposite that of a 1911 type safety.
That is to say that the safety lever is in the "up" position to fire, and "down" position engages the safety. I have trained myself with a 1911, and have fired 10s of thousands of rounds through it and guns with the same type safety. I don't fancy carrying a gun that works opposite from what I am very used to using.
Depending on what this gun will be used for, it may make a fine choice. I still have mine, and it comes out to the range on rare occassions. It shoots well, and has been 100% reliable with many different types of ammo. The trigger stinks, but most of the older S&W Semi-autos had lousy triggers.
Have you considered the Springfield XD-45 line? 14 rd. mags, much lighter, dead balls accurate, decent trigger, and I find that it fits my hand like a glove. There are a ton of very good semi-autos out there, but you must consider it's purpose if you are to pick one that will suit that purpose.
The 4506 ranges in price, according to my books, from $680(NIB) to $210 for one in poor condition.
Hope this was helpful. Good luck.
WG840