The decision to drop exfat is most unfortunate from compatibility point of view. I'm afraid it will have negative impact on adoption rate because average user will not be convinced just by saying "oh, you don't have to pay for Microsoft!!" Hopefully our foss-fanatics are happy now that we can have our own, incompatible geek-way to annoy average users, so we can express some creativity in explaining why it's good thing. Luckily, SDXC is not that common yet, so it might take some time before serious issues arise - but be assured, this decision will definitely not receive any understanding or mercy in hands of reviewers.