well well you can't use batterypatch and Cpu power controle together
only 1 of them

the differences :
Cpu power controle : is a power controle -_- you configure your profile and try pre configured profiles and other configurable settings
and there are some of batterypatch features in it
ex : vfs trick and cpu_sleep (if) script

batterypatch : aims to give the batterylife to N900
compatible with HD recording and can easily controle max/min freq (by editing /usr/share/kernel-power/overclock)and no need to use many profiles ... and it solves some issues
ex: solves the lag sometimes caused when recieving call by setting minfreq to 720 when a call is recieved
and have more configs in dbus-scripts-settings
ex: if you locked your phone while the keyboard is opened and then closed and left the keyboard right away then after couple a sec N900 will send a dbus-signal ( as the system is not active) and will activate cpu_sleep
.. this feature is not included in cpu power controle

although might not explained enough about cpu power controle because i haven't tried it (only saw what it contains)

INSHORT : you cannot fully compare batterypatch and cpu power controle
because they are different from each other