Well. Support for writing on NTFS volumes should be added to Ubuntu by default, I guess.
The new Knoppix supports it already, the new Sabayon Linux does and it is planned for Linux Mint.
Although it is still labeled as beta (but might be final until April judging from the development speed) it isn't supposed to cause any data loss.
The slowdowns should be fixed by today's NTFS-3g update.
I think that I will start a poll in the feisty development channel.