I agree that on a PEG basis, JCI is not overvalued but not compelling either.
My comments are more in relation to peers, on a sum-of-the-part valuation based on 2013 earnings. Pick their competitors in each of their business (do not limit yourself to the US, as say the automotive division sell a great deal into German-based manufacturers) and compared valuations.
I feel that a growth multiple is applied to the whole company whereas it should only be on 2/3 of it. Plus the assumption behind the automotive business are pretty bullish to say the least.
But I'll be honest I don't follow the stock closely, just their european-based competitors.