The right mask can make a huge difference in the quality of your sleep. You need to try out many different masks before you find one that is right for you.
The one mask that I finally decided on was the Phillips Respironics Dreamwear mask. I loved it because it was light and I could finally sleep on my side.
Also, be aware that the CPAP suppliers are paid by the manufacturers to push their products. The company I got the mask from kept pushing Resmed masks (which I hate) and would never offer the Respironics ones. I got a Respironics mask in one of my sleep studies and it was great, so I switched. I took a leap of faith buying the Dreamwear mask and it has been wonderful for the past 3 years.