I have only tried Quick Support. Tried it twice and noted that, every time, a local person is required in order to answer the User Account Control (UAC) Yes/No. The other guy (won't mention his name teamviewer) doesn't have that problem.
The full client should prevent the Windows Secure Desktop UAC dialog from triggering. The Quick Support client cannot do this. The assumption is someone is at the other end for the active support session.