A home switcher essentially does the same thing as doing it manually. Be aware that using the stock home only causes sense to sleep. It still uses some memory resources but far far less then when it is running. HTC also replaced a lot of the stock android apps so things like the contacts, dialer, calendar, etc are still the sense versions even though you are not using the sense home. When going stock you also do not have access to the sense widgets. Only the android ones are available.
It does make the phone feel faster and frees up quite a bit of memory.
