Not too bad. It was a pale ale that came with the kit. Some of the bottles didn’t carbonate very well, but they’re plastic. I should get some glass bottles. Buy a case of Grolsch maybe.
Did the plastic bottles come with your kit? I have never had a problem with plastic bottles designed for hombrewed beer. I always use one or two when bottling when I am bottling the major portion of my beer in glass bottles. I use them as a means to easily check on carbonation level. The Grolsch are supper, especially if you expect a very high carbonation. I use the Grolsch capped bottles for my sparkling ciders and Meads.
Dave, the plastic bottles with Mr. Beer are fine to use (we use them). It could be that the lids were not tightened well, or there was not enough priming sugar in each bottle.