I wear a 38-40 pant and they are snug. I would say true to size stated.
Yeah, forgot about the differentiation. Right on with his analysis though. I have the regular pants and they fit but are snug.... loose/baggy are perfect.I have a number of pairs of oakley pants. Generally they fit true to size IMO. The difference is going to be what "fit" they specifiy for a given size. They usually come in slim, regular, and baggy or loose.
For example, I have ~ 39" waist. While the regular xxl fits ok the loose xxl gives a little more room for movement.