The firmware upgrade will fix the font issue, which is a big one.
The upgrade also changes the way the Kobo goes to sleep/powers down, and that feature has a number of people in an uproar. I think it is far outweighed by the benefit of fixing the font issue.
The upgrade also lets you hide the 100 free ebooks, which is good.
I'd grab the upgrade as soon as it's available, as the benefits to me are much greater than the negatives.