I see theres a few manufactures Who make a fixed cogs like Token/Shimano/EAI are they all about the same in quality or is one better than the other? I had a cheap Dicta one once and god knows how but it cracked.
I just use the cheapest I can lay my hands on but I would suspect going for a brand name might mean a bit better quality
I had a stock one off my Langster which I replaced with a Surly one. Both were great but the finish on the Surly confirmed it's loveliness. It's such a simple but important part, I think it's worth spending on. Sorry but I didn't try the other brands out.
If you're breaking/skidding then you have extra forces going into quite a small piece of metal, I'm not surprised they crack once in a while. I've heard an argument for a bigger amount of teeth but the same ratio to spread the wear out too.