I've had a real trauma finding a pistol holster that I was absolutely happy with. I've gone to stupid lengths to find a suitable one, even going as far as buying a obsolete 1950s British Army webbing holster to try out.
Left: The ACTION Navy Seal holster. You can see how the flap securly retains the pistol. The holster also has a smal pocket for a spare magazine and has three MOLLE straps on the reverse for you to attach it to a duty belt or MOLLE rig. This holster can be used with medium to large framed pistols, and works exceptionally well with both my SIG P229 and Glock 18C replicas.
Well, long story short, I have finally found a modern and cheap holster that is absolutely what I want. The ACTION Navy Seal ICE MOLLE Pistol Holster is available from eHobby Asia via their eBay store and cost a paltry $21.99 (including shipping).
It only took about seven days to arrive and when I opened the parcel I was immediately pleased with the quality of the holster. I have had all sorts of makes from the cheap Viper to more expensive Webtex models, but have been left very unsatisfied with them. One of my criteria based on my experience in the field was that the holster had to have a flap enclosure, for maximum security of the pistol. Speed draw was not an important aspect, so an 'open' holster was not necessary.
It seems the 'fashion' to have these open topped holsters on drop-leg rigs (the pistol being secured usually by a thin strap with goes over the heel or hammer of the pistol). I found this type of holster far from secure, and on my first outing a fellow player lost his pistol from one of these, which perhaps prejudiced me against them.