According to NEC, version 1.07 supports more media, but all the new supported media types are not recommended. So if you don't use these types of media, you won't feel any improvements over 1.06.
If you want bitsetting, you have to flash Herries 1.08, which is a modified firmware version 1.27 from HP. The media support and writing strategies seem to be almost identical to NECs 1.07 firmware. I'm using this one! (Thank you, Herrie!)
If you want higher burning speeds and bitsetting you'll have to go for Herries 1.07b7 firmware, which is supposed to produce best quality burns from all the betas released. Although there seem to be some problems with DVD+RW...