North Africa was pretty much ruled by the British. The early days were a real debacle, as both were getting a real feel for each other when the Americans joined the British in November of 1942. The British had absolutely no confidence in the Americans and thought of them as wimps. The truth was that the Americans were GREEN at the time, and certainly didn't have the experience that the British already incurred against the Germans. But while true, the Americans weren't given a fair shake because a lot of early mistakes were due to leadership and poor communications between units and especially between British and American allies. You can also attribute this to some pretty poor tactics and lack of knowledge of the terrain.
Many times infantry were used where they shouldn't have been, and without adequate backup and artillery support. Men were simply slaughtered and it had nothing to do with poor moral or lack of experience on part of the Americans, although all did figure into the long-term equation.
As the campaign advanced, the Americans did prove themselves. Just look at the performance of such units as the 34th (Red Bulls) and the 1st (The Big Red One) Infantry Divisions, to name a few. 
Proud Daughter of Walter (Monday) Poniedzialek
540th Engineer Combat Regiment, 2833rd Bn, H&S Co, 4th Platoon
There's "No Bridge Too Far"