I live not too far from their headquarters in Elgin Illinois and have been inside their facility there.
I've used their valve train parts over the years and have had no issues.
I believe everything they sell is also made in the US.
They primarily deal with good quality OEM spec replacement parts but they also have a Performance line of parts that appears pretty good.
I don't think they have any crazy-over-the-top HP parts but what they do offer is decent quality at a decent price IMO.
You won't find the latest and greatest cam profiles but parts quality is very good. I've used Elgin Pro Stock hardware in vintage race motors where roller rocker were prohibited and they lived on a pretty agressive solid flat tappet grind road race cam.