A very early MeeGo development release has been available for a few weeks and there is also an Intel App Store in development. The latest news for MeeGo is that it's using Btrfs as its default file-system, as confirmed on the mailing list.
MeeGo is now the first high-profile Linux distribution that will be deploying Btrfs by default. Btrfs has been in the mainline Linux kernel since the Linux 2.6.29 release and has been an Anaconda installation option within Fedora for a few releases. With Fedora 13, when using the Btrfs file-system it can even provide Linux system rollback support.
Our initial Btrfs benchmarks found it to not be a performance king, yet, but that was about a year ago. Since then the performance of Btrfs has improved while at the same time the performance of EXT4 -- the file-system currently used by a majority of the Linux distributions -- has regressed. Here are our most recent benchmarks comparing the performance of EXT4 and Btrfs using the Linux 2.6.34 kernel. Two months back we also showed how Btrfs compares to Reiser4.
Beyond offering competitive performance, Btrfs offers a greater feature set than the EXT4 file-system that evolved from EXT3. Btrfs offers support for online defragmentation, online balancing, transparent zlib compression, sub-volumes and snapshot support, object-level mirroring and stripping, and block discard support.