Researching a bit on chargers for the iSi gourmet whip, its clear that prices range quite a bit. You can get cheap chargers at less than half the price of the iSi's own. Regarding quality, its relatively clear that NO2 quality in itself is not going to differ much, but the added oils might. From what I can read, brands like Kayser and iSi are very "clean" and brands like Best Whip a bit less so, though still at better end of the range.
Has anyone seen good tests or have anyone tested themselves, because cream chargers like Best Whip (MOSA) cost about 1/3 in europe.
Rasmus