A video by Battlefield 3 fan "PTFODylan" has compared the input lag present in the PS3 version of BF3 as it was before the recent patch to what it's like now, post-patch. (If you didn't catch the news, an update went live the other day that improved the issue that's been plaguing PS3 players for about a year now.)
According to his measured tests, the game is now more or less in line with other 30fps shooters on the platform, with about a 100ms input delay present versus the previous 200ms. You might be thinking any delay being there means the issue isn't fixed, but Dylan says it feels intentional and natural and gives the "weight" to handling the gun you'd expect, instead of feeling sluggish.
So, if you haven't yet grabbed the update and/or put BF3 back on the shelf thinking this problem might never be fixed, now's the time to get playing again.