The number of discs that the Lite-On will write to at 20x and 22x is very limited. If I remember right, its limited to Taiyo Yuden only. Even with the OverSpeed function enabled, you're only going to be able to write at 20x in most cases. The LG is a bit more flexible as it will write to both Verbatim and TY media at 22x and a number of other types at 20x.
The iHAS122 is similar to the other drives in the iHASxx22 series. The differences between it and the iHAS422
is that it lacks support for LightScribe and SmartErase, which you probably aren't going to miss. It still features stuff like SmartWrite and OverSpeed though.