I can attest to this. Having run quiet a few freemium model sites, the time and energy wasted on unwanted support is astounding. God forbid if something goes wrong, some people will take time to email you just to yell at you. Still can't understand how people expect absolute perfection for something they aren't paying a dime for?

However, one thing I noticed is that freemium clients are more likely to click on ads and subscribe to your social networks than others. Some pain for some gain I guess.