Qatar's diplomacy is at some level now delegitimized by their aid being tied to a party. Qatar aids parties that, in return, they influence. Rather than being a respectable third party, Qatar has now interjected itself in Egyptian, Libyan and Syrian politics, for better or worse.
The UAE and Saudi Arabia are a bit different because now they can help in future situations without question (or as much controversy) on how objective they can be. While Qatar has a stake in the MB, the success of the MB means more influence for Qatar."