There will be no increase in Tasks if you upgrade.
Ads will definitely increase.
As a Standard member, you get 1 guaranteed Standard ($0.01) ad daily. Premium members get 4 such guaranteed ads daily. Also advertisers have the option of choosing the Premium filter to target ads to Premium members only. So Premium members definitely have a lot more ads to click than Standard members.
For more info, please check these 2 pages.
>> My Account: Premium Account - ClixSense
>> ClixSense Affiliate Program - Refer Others And Multiply Your Earnings!