I haven't bought the 33rd, but I have several of the KCI 15 and 17rd version. Both of which required the removal of extra plastic inside of the magazine and on the follower.
If you don't mind filing and fitting them they may be worth the money, but I wouldn't recommend thinking they will work straight out of the package.
Oh well, I guess I will go for them online. I had seen a lot of bad reviews on the KCI mags but Im willing to give these ATI mags a shot based on this video review. Thanks for another great video review.
I did get one of the 100 round drums for the AR15 and I can't get it to fire a full 100 rounds without a failure. It's also Korean made, but marketed by another company.
Between me and my buddy, we have several of the Glock 33rd mags and so far I've not had any issues with them. Others have reported pretty good luck with them too.