We had the lids drilled to fit a #9 stopper and airlock. We've tried a lot of other things in the past (drilling canning jar lids, etc.) but nothing has been truly airtight yet until we went with these bail-top Fido jars.
The ferments have been excellent, now that oxygen is excluded.
I assume you still weigh down the cabbage so that it is below the liquid line? I've never thought about it in terms of using a container with an airlock. The kraut crocs look very nice, but are pretty expensive. I suppose I could also use one of the 2-gallon food-grade buckets I have with lid and airlock (assuming I don't want to use it for wine/mead anymore).