bhushansharma - 12:14 pm on Jul 5, 2013 (gmt 0)
As your first question is "Can we set up multiple accounts for different clients? " about different clients.
Yes you can handle different clients with different account with same place, there is option in Google Adwords to handle multiple accounts with the help of My client center.
Last and final answer is, there is not any drawback if clients not handle their account themselves.
Your second question answer is, yes client can pay with his account and you can manage that accounts.