I'm watching and comparing, and I know Ron is, too.
You said similar in age, how old were they? When you say Her RIR, I'm assuming that your stock is bred true to standard. My Basques have a ways to go to meet the Spanish standard...
I did a taste test of hatchery Barred Rock cockerels against EO cockerels - the EO was much darker in the leg and thigh than the BR and had way more flavor.
The roos were all 14 months old. The heritage RIR was from hatching eggs that I got from EBay. They were ok at best. After doing much research on heritage breeds, I found that none of the old timers knew anything about the "George Ryan Line" that she sells. The color was dark and we had some good horn colored beaks, but the legs were too light but too many popped up with white in the tail, and several cockbirds (dispite being hand raised) turned mean and nasty. I sent them to the stew pot early on. This last fella was even tempered, and very large, but suffered a recent unknown injury. I have a great looking Underwood cockerel growing out to replace him.
My Marraduna flock are coming along right nicely. I hatch and grow out more than I should (my feed bill is stupid high). Selling my pullet culls are no problem, but the cockerels are a very hard sell. I'm keeping the largest, typiest, friendliest birds for myself. Love the broodies. I really want this to be a major trait in my flock. The variety of egg color that I'm seeing is all over the place. We get creamy to cherry brown. Big heavy eggs from the hens (average 62g) with the pullets starting at 44g and working the way up on the scale. I haven't done much weighing with a scale but use my hands to heft and feel whats under the feathers for body type. I wish I could figure out how to upload a video. I would post one of the big ol' flock out to range (they share a space with my GOS boar pig). Mostly they stay in that paddock but do find space to come under the fencing looking for greener space and my poor ornamental plantings! Seems all the chickens love to perch on the edge of a pot to scratch out whatever I have planted. Still love em' though.
The fastest growing bird that I have hatched was a black sex-link cockerel. I may hatch some more for processing purposes. But I have so many baby basques growing out that I may wait until the fall for this project.