Personally I wouldn't leap straight onto using the thermal lense immediately. Sure they are better anti-fog which would help on very cold day but the thermo-cured single pane lenses are pretty decent a lot more durable and can be rinsed with water if they get mucky. If you've got the money to spend then sure pick up a thermal but I wouldn't fit it immediately, see how you get with the standard lense first.
I've loved vforce goggles for a long time and have rarely had any issue with the standard lenses.