I think you can't really compare the Dignitas preparation to the N for injection that most people obtain from A. From what I've been able to ascertain from the videos, the Dignitas preparation is a much more concentrated dose in a different form from the vials meant for injection, but the Dignitas preparation still tastes awful because the patients complain about the bitterness and chase it with chocolate candy. I doubt there are many people who could tell us for sure what the difference is.
The Dignitas preparation is 15 grams of pentobarbital in 50 ml of water.
The brand that A sells, Pisabental, is 6.3 grams of pentobarbital in 100 ml of carrier liquid. From researching other veterinary pentobarbital formulations, it's probably a combination of water, alcohol, and propylene glycol. So 2 bottles is 12.6 grams of pentobarbital in 200 ml of liquid.
As far as we know, no one has volunteered to do a taste-test of both. lol
They both taste like crap; we all know that. The Dignitas preparation tastes worse because it's more concentrated, but there's less to drink.
If you do a search for "Pisabental," you'll find numerous reports of people who successfully used it to CTB. There are even people who drank it without anti-emetics.
N tastes like crap. That's just the way it is. For some people, that's going to be a deal-breaker, and they'll need to use a different method or stick it up their butt.