It does not matter, which name they give those primes.
What "counts" for me are an good IQ ( low CA, high resolution,...) and an fast AF.
+1 on the lower prices. It is good, that there will be a bit of price war. I know, that some of the guys here think, that only high-priced lenses are good lenses. But I believe that Canon adds an very big plus on the prices to optimize their profits. Nikon does it too... Now Sigma has the chance to increase their market share in these class of lenses.
And if these Sigma lenses are just a little bit lower in IQ than their Canon counterparts, one of the 500mm lenses will be mine.....