I'm not sure about that. The French army relied heavily on conscription, not volunteers and I think that possibly told when they eventually began running out of veterans and what not from Napoleons earlier campaigns. Sure the British had a lot of prisoners and people who were given small option to join, but the majority of it was a volunteer army.
The British also trained with live ammunition, which no one else did and also supposedly had better quality gunpowder. The British armies main weakness, as it always has been, is it's relative size which has always largely been down to the cost to maintain such a force rather than the size of the potential population. Whereas France largely focused on size. When you look at the potential man power of the French army in the peninsular compared to that of the British/Portuguese/Spanish, the numbers are rather frightening.
From what I've gathered about Napoleon his victories had more to do with speed and tactics than with troop quality. Not to mention promotion by merit.
Finally, we had the god damn Scottish and Irish.