I actually should have worded it differently though. I think Marc is one of the dub's better voice actors. I don't think he is the best and yeah, Eric Stuart is a brilliant voice actor like you said. I actually think Marc's Unova Pokedex is good though. But he did a BRILLIANT job as Commander Saturn and Dr.Zager in my opinion. He also actually voices Casey Jones very well in TMNT 2003.Marc's decent in his own right. That I'm not denying. But his Tepig, Krokorok, and Unova Pokedex voices sound very forced (his Krokorok in "Battling the Bully!" grated on my ears...my little brother asked me if it was mentally challenged). He sounds A LOT better in the 4Kids Yu-Gi-Oh dub IMO. He shines as Duke Devlin and Astral in Zexal.
Eric Stuart is my favorite overall. Such range, delivery, and a hilarious James. And not to mention a Brock that actually sounds like the Japanese seiyu Yuji Ueda (something Bill Rogers has never even come close to doing-- he sounds like a 60 year old burly trucker now IMO).
Tom Wayland is a terrible voice director. He made Stan Hart sound BAD in one of the most recent dub episodes. I'm sure Marc would be much better with 4Kids/FUNi/Viz/Ocean/AB Groupe/even that speedy dub of DBZ in Malaysia).