I know it's been a while since you posted this.
My experience with the Advantage Arms Glock conversion kits has been mixed, and I've owned several. They're not very accurate, for a .22, and the reliability isn't that great. I would rate these as terrible guns. However, looking at them as a training device, the accuracy is acceptable, and you can practice with your exact trigger and gun. You can also use your regular support gear. This is a big advantage.
So, if you want one to shoot, skip it and get a buckmark. If you want a subcaliber trainer, go for it.