It really depends on the purpose for which you're buying the holster.
If for actual duty use then your department will have made the determination of holster to be used.
If for competition then you may want to look at the Safariland 6280 or 6285. The 6004 is a leg strap tactical version but is not allowed in most types of competition.
All three of these models use the rotating hood locking system... very easy to use and quite fast to draw.
Fobus makes a very inexpensive retention holster. It's a variation of their standard holster, but has latch that locks into the trigger guard... the latch must be pressed before the gun can be drawn. Price is right but as an actual duty holster there have been a lot of criticisms in the US about these... apparently they don't stand up well.