I agree that SF/Tahoe is the better choice.
1) As noted SF is a lot more pleasant weather in February than Vancouver
2) I consider Whistler a considerably more advanced than average ski destination for North America. I think it's poor for beginners, can be demanding for intermediates with long runs in sometimes changing snow conditions as you descend. Still great for well conditioned intermediates, but if you're still improving and this is your first time in North America, why not go somewhere more mainstream then come back to Whistler when you would appreciate it more? The areas at Tahoe range from very expert to very beginner/low intermediate friendly.
Keep in mind that historically February is the lowest snow fall month for Whistler. I thought that seemed strange, but this was according to their own chart in their ads in the various ski magazines.
A classic example of misusing stats: 40 year data in inches here:
When you consider that monthly standard deviations are 35-40 inches, those snowfall differences are essentially meaningless. Particularly when February is in the sweet spot between low light (important in Whistler Alpine) and 1/2 hour earlier closing time Dec/Jan and more likely sloppy conditions on the lower mountain in spring.
Note to Philpug: The above is a perfect example of when experience is more important than raw numbers to answer a question intelligently.