A lot of the groupons are extremely worth it in terms of what you get for the cost.
Very much so. The $99 three month VIP membership saves you $66 off what 3 months of a regular VIP membership would cost. I think once my membership expires in May, I'll use Groupon deals from then on to save myself some money.
EDIT: The above is based on paying for a year in advance. If you pay by the month, the Groupon deals save you even more.