The stock price is not relevant for a final investment decision.
You could compare 5 year average of the following ratios.
1. Return on equity (preferably higher than 12%) :
2. Debt/equity Ratio (preferably lower than 40%):
3. Price/Book ratio (preferably lower than 5):
4. Price/Earnings ratio (preferably lower than 10):
Both companies are comparable for the first 3 ratios, but Microsoft seems to be cheaper relative to it's earning power. To be comparable, Google stock should be trading around 325$ per share to have the same value as Microsoft.