NTFS read-write is actually one of the oldest and probably also one of the most mature (I don't mean the original NTFS project from 1995 but the one which restarted in 2000). Its code base is 9 years old. The core of the write functionality is actively used since 2003 in quite many softwares. Not necessarily as a full-feature read-write driver but as part of other softwares which had a very good code coverage of the today complete driver.
In fact some people reported that it's sometimes faster than ext3. This is not so surprising if one compares the file system designs. Ext4 solved the ext3 performance issues. In all our recent tests ext4 performs better than NTFS-3G.
There is also a performance oriented NTFS-3G driver, mainly for consumer electronic device makers which is 3-20 times faster. On a T9300@2.5GHz it performs 1.375 GB/s write speed. No typo, it's gigabyte per second and it's still far to be fully optimized.