I always go to eHam.net for reviews. One review of the Godar antena:

http://www.eham.net/reviews/review/93779

Several of an AM Terk unit:

http://www.eham.net/reviews/detail/8505

Looks to me like the Godar placed outside and up a few feet would work great for FM and scanner freqs. You will want something to use as a ground plane. For $99 I might try to roll my own first, but I have whips and a deep junk box already.

I spent a night listening to the local cops ( see http://www.radioreference.com/apps/audio/?mid=178 ) and it was boring. Most systems now are also trunked, meaning they use several frequencies, so you will probably need a trunk tracker scanner.

A Ham doesn't know what antenna overkill is...