In my experience there are good and bad pilots from both camps.
Grumpytroll has described a scenario in the US which also applies as a generalisation of the way it is in the UK also, especially in the mid nineties onwards with regards to trainers and training.
Where I currently work we try and maintain a balance between former mil and purely civilian pilots as both groups have something to bring to the job and we all have something to learn from each other, we regularly swing from 60% mil / 40% civ to 40% mil / 60% civ and it causes no issues.
The one thing the military training system does have to it's advantage is the ability to chop people who are not suited to flying as a career, the civ world does have a problem with a few who just threw money at the problem.