The TS-2 is what I use and I quite like it.
3 of them are 17 years old and we just purchased a brand new one. Of course everyone likes the older ones ... hah.
Anyways, in my opinion you do not NEED to buy the more expensive one. If you are truing 10+ wheels a day, yes you need it (in my opinion). For home mechanic work, the TS-8 is just fine.