Yes, if you can wait. If I had known that a new firmware was coming out this quickly, and if the only difference were the zoom in speed on the playback, I would still have bought my camera first thing. This camera is so much fun and I've been eagerly awaiting its arrival since it was announced three or four months ago.
If you look at the firmware upgrade that you can purchase for the 2500L, you'll notice that its not very major. In fact, after hearing about it, I didn't understand why they would even both to offer it as an upgrade. I truly hope that if Olympus improves the focusing or speed in a major way, that they'll offer an upgrade.
We'll have to see.