I run 12/40 during the winter for when my warrior is chugging through snow or pulling a trailer or logsplitter, and 14/40 for the rest of the year. These gearing setups work perfect for me.
I like the stock gearing. A little slower on top than th 14 front but i like the power for climbing and pushing through thick mud and going over rough terrain like rocks and logs. I hate the 12 tooth front. Just runs out to fast!