where a lot of people run into battery problems with 3rd party launchers is they forget to clear the widgets and shortcuts off of their other launchers. for example, if you want to use LP as your main launcher, you should also clear out all of your homescreens on the stock launcher, otherwise your widgets and shortcuts will essentially be running twice. to the OP, if you bounce between stock, LP, and ADW, and you have widgets set on all 3, you are basically running those widgets 3 times, which will kill your battery/decrease phone performance.
i have used 3rd party launchers for the vast majority of time owning an android device, and have NEVER seen any battery or software issues.