From personal experience, the gas company is only required to provide x amount of gas per 24 hour period. So, during peak hours (think Thanksgiving turkey in the oven) the gas pressure in the lines is low, and the turkey does not get cooked because the oven was not hot enough, even though you set it at the correct temperature.

If I was going to re-do my kitchen I would get an electric oven - probably a convection style due to the good cooking results I have seen.
The cooktop might be gas for precision hear control. I would also investigate induction type cooktops.