I got an AK2i about a month ago, and I don't regret it one bit.
I needed for my new XL so even if this update would have come at that time , it wouldn't make any difference for me because the R4 will still not work on any DSi.
I'm glad though the firmware got a much needed update.
What worries me though, is that new games with AP will have to be patched 1:1 or nearly so when they come out.
It's a big task and as an R4 owner you gotta pray that there will always be somebody creating patches for new games all the time.
But yes, for the time being it's a great thing to have a new firmware.
It doesn't affect my decision to buy another card though.