i upgraded to 10.7.4 and the battery life on my 2010 13 inch macbook pro has improved it lasts just as long as i did on snow leopard and my macbook runs cooler.
That's not a leak! Safari typically takes about 200MB ram. Since Lion came out it has been accruing ram as it sits being unused. I would wake up my computer after not using it all day and it would be using a couple gigs and my computer would be totally locked. Now it continues to use the same amount. Therefore it is fixed. If you don't have enough ram to facilitate 200MB then its time to upgrade!