I use the UMAB ones, which have 7 grades. I think the 4th grade (green) is supposed to be about the same as a pine board in force required to break it. Not sure how accurate that is though. As you say you do have to hit the re-breakable ones in the middle, where with pine you can drift off a bit more. They're not cheap, but mean you avoid buying pine every week!I’m not the biggest fan of rebreakable boards, but I don’t hate them either; I’m pretty much indifferent to them.
The one thing I like most about them is they seem to have a significantly smaller margin of error regarding the striking target. I’d imagine breaking them in the air would be a lot harder than wooden boards. Have you noticed a difference?