I would prefer the fixed fund at this point because it has no interest rate risk. At some point interest rates will increase and the value of the bond fund will decline as a result but the fixed fund will not decline. Since interest rates are at historical lows, the likelihood of interest rates increasing seems much higher than interest rates declining, although when the change will happen is not real clear.
If something cannot endure laughter.... it cannot endure.
Patience is the art of concealing your impatience.