Funny, but this isn't the first time I've heard this about Eagle/Scat. I suppose it depends on what you build, and "how many". The majority of our experience has been with "un-Chevys" (we build about 30 engines per year, more than 1/2 are Pontiacs). We have, however, tried pretty much all the available stuff in the small block circle track applications. (If you wanna know what holds up and what doesn't, circle track is a GREAT "proving grounds"). The Chinese castings consistently "beat out" # 2 and 4 mains.
We have one case where an Eagle 461 "kit" was used in a 400 Pontiac. He put 751 1/4 mile passes and over 3K street miles on it. Consistently "finished" in the top 5 in points at two tracks over a 4 year period, turning 10.30s and .40s, 3.400 lb. '70 Firebird. The one time we tried a Scat 4.25" stroke, we couldn't balance it without adding weight to the leading edge of the counterweight (not good). Others have reported the same issues with the 383/400SB castings (9000 series).
We heard about quality issues with the Eagles, but have not seen them. In more than one case, where it was said the crank was "out", the crank was fine and the BLOCK was bad. This falls under the "chicken or the egg" question. Often, crankshafts get "blamed" for problems in an engine when the issues ly elsewhere, the crank being "caught up" in the wreck (so to speak).
IMO, if you have something that "works" for you, go ahead and use it. For those that aren't "in the business", sort this out best you can! Neither are "wrong", just different POVs.