Not liking a specific manufacturer’s designs is a particularly difficult problem if you work for an agency that has a one-gun-fits-all policy, meaning that only handguns from one manufacturer are authorized for on-duty and in some cases off-duty use. Some agencies are very strict about their one-gun policy and others are more flexible and require sworn personnel to carry the same service handgun but allow a backup or off-duty gun that is chambered in a different caliber and made by a different manufacturer.
One reason why Glocks are so popular with police agencies is that the company makes a complete line of pistols ranging from full-size tactical models to compacts and subcompacts. The advantages to issuing the Glock pistol for patrol, concealed, and off-duty is that you have the same manual of arms for each model and the magazines are interchangeable as long as they are the same caliber.
Most other manufacturers do not offer this kind of versatility. SIG, for example, does not make a subcompact pistol in a substantial caliber that fits in an ankle holster, let alone a subcompact that also has magazine compatibility with a full-size or compact variant. So if you are a fan of SIG pistols and you work for an agency that wants to have one make of handgun for all purposes, you are going to have to learn to love another make of gun, likely a Glock.
Another reason that officers can sometimes hate their issued sidearms is that the caliber is wrong for them. This problem goes both ways. If you love the .45 ACP, you may feel that the 9mm does not offer the stopping power that you need. A worse problem is if you find the caliber of your issued sidearm too powerful.
Finally, when an agency has a “one size fits all” policy, you can end up with a weapon that doesn’t fit your hand. Some agencies want to maximize your firepower, so they issue double-stack handguns to every officer. Sure, it’s great to have 17 rounds when you need them, but if you can’t wrap your hand comfortably around the grip of your weapon, then you may have a hard time accurately shooting those 17 rounds. Remember, it’s better to fire seven rounds with accuracy than spray and pray 17.