"Has anyone replaced there battery and got the same result?"
Well since I am past my warranty period and am unable to find time to reach an Apple store in the next few weeks, I decided to risk buying a battery from eBay at the fraction of the cost.
I do think SL had altered something with my original battery, as like a lot of other people here, I only noticed freak premature shut-offs after SL's installation. I had the "service battery" warning btw too.
However, I installed the new battery and calibrated it as per Apple's own instructions, getting a good 4 hours use out of the battery on first use (and that was with the keyboard lit and doing various tasks). I eventually got the low battery warning and let it go to sleep over-night, then fully charging the next day. Since then I am using the battery on and off, and have made sure to set a reminder in iCal to calibrate once a month. The "service battery" warning disappeared with the new battery, and am now getting consistently good life out of it, same as before SL. So, there was indeed an issue with the previous battery. As to wether SL actually did anything to make the battery faulty I can't say.
All I know is the problem definitely gets fixed with a new one. The whole thing has made me more dubious about upgrading OS' from now on though.
One other thing. For a few months my trackpad has been suffering from being unresponsive sometimes when trying to single-tap. I had to double-tap (right-click) for the single tap to work again, so I assumed it was a software bug. However, since the new battery this hasn't happened once! So perhaps my old battery was pushing up against the trackpad as others have reported. With this in mind, perhaps my old battery WAS faulty before SL, and SL shut down prematurely as a safety measure maybe?
