Rightfully so too. Mac owners seem to be rushing out and updating to Mavericks faster than they have for operating systems in the past. In the first 48 hours, Mavericks has been installed three times as often as Mountain Lion over the same time period and has already hit 5.5% market share across North America.
From a Chitika report:
Pre-release OS X Mavericks exhibited low levels of usage due to beta-version activity from developers. 24 hours following Mavericks’ public release the afternoon of October 22, adoption rates hit 5.5% of all Mac OS X Web traffic. This significantly outpaces OS X Mountain Lion, which took approximately four days to reach the same level. While Mountain Lion wasn’t particularly expensive ($19.99), it’s likely the lack of a price tag on Mavericks spurred additional users to upgrade in the early going.
It’s amazing what free will do to market penetration.