IMHO Hitler would have been a lot better off if Mussolini had sided with the Allies. Hitler wasted a lot of time, men, and resources just bailing Il Duce out of predicaments which he stupidly got himself into.
True, but would you want allied forces, particularly air forces, operating from the Po River Valley in 1943 instead of 1945? If Mussolini had flipped or been deposed you might this might have been the result. Also, a good chunk of the Axis forces -- most of the leg infantry -- then operating in Tunisia were Italian. If Italy sits out, what happens to the Afrika Korps? Not all the Italian troops were unwilling to fight...