If you are looking at FKINX, the ER is .64. VWINX has an ER of .25 and their admiral shares (VWIAX) have an even lower ER of .18.
So on costs, Wellesley is way ahead. For performance comparison, you can use Morningstar's chart. It appears that the Franklin fund outperforms Wellesly, but the bonds are of the lower quality - so you are taking more risk in exchange for higher yield.
You'd have to decide whether the risk is worth it to you.
Disclosure: we used to have the Franklin funds. I was uncomfortable with the risk and moved to Wellesley.