I had a thread here about 3 years ago i htink asking about the same thing.. hehe I have a 3 racing comm lathe with v blocks and i must say its great!
bearings (as i understand, will freeze up later on.... because bits of the comm may get into the bearings and screw it all up)
So it is best to get the v-blocks instead.
becareful of shimming the 3racing lathe and also "some assembly" is required.... when I bought mine... so if u are no expert... this is not hte lathe for u