In theory, the stability of the bonds should be reflected in their bond rating - more risky bonds will pay a higher dividend/interest, but are more prone to failure. I don't know how accurate they are on municipal bonds - that isn't to say that they're not good, but I'm not experienced and haven't followed.
I am thinking of maybe getting into some muni bonds. Might look into it tomorrow. Time to rebalance anyway.
Though not a financial site, it does give the info on the bind that pension obligations have put local and state municipalities and their effects. Good info. for one who has invested in municipal bonds or is considering it.
http://www.pensiontsunami.com/
RE: Bonds. Muni or otherwise. When if inflation hits, the value of those bonds will fall along with the rise in interest rates.
Ideal time to invest in Bonds, is when the interest rates are high and expected to decrease.
Just something to keep in mind. It a difficult investment environment right now.