From my personal experiences and various forums regarding the 10/22, it's almost as if each mag and each 10/22 will have a varying degree of reliability. As others have mentioned, get 2, what should be "identical" mags from the same manufacturer, and one may run great, the other not so well. To throw another variable in, so does the ammo, as do other factors like the use of a "tuff buffer" or similar type of polymer buffer instead of the original steel buffer.
I personally had good results for the most part with HC3R which are somewhat readily available in Canada both in store (my local LGS has them) and online. Just another one to consider if you have access to them. Price is comparable as well. Might be worth your while to try out 1 or 2 different models used until you find one that works best. You see Butler Creek and other 10/22 mags being sold on EE regularly as well.