The reason so many US Police Ops use Bell singles is that they are usually sourced at deep discounts from the US Military, which also provides a large pool of type-experienced Pilots with many hours of similar tactical-type flying. Most also use surplus FLIR and spotlights too when so equipped. It's a good system for anywhere and the specific experience equals safer ops than one might normally expect. Bigger departments with larger budgets (and perhaps other requirements to consider) have other choices but for most it's either the Bells or perhaps a Robbie, and none of us want to see
that 
My local PD has 2 Bells and watching our main Pilot fly is like watching a Bolshoi ballet. He's flown this type since the 60's in Viet Nam. I'd fly into hell armed only with darts to take on the devil with him at the controls
