I'm having a hard time finding objective reviews / comparisons of these two 'lite' clients. Can someone who tried them both give some comments?
I think multibit shines in its ability to handle multiple wallets, which is very important to maintain anonymity and information leakage through "change" transactions.
However, Electrum is currently a much more feature rich client that allows you to create wallets and spend bitcoins from an air-gapped computer with no internet connectivity. This is the ultimate security for Bitcoins.