I've been running 6 Norma Dasher since it came out and having very good luck with it. I didn't have a 6BR at the time, and wanted to go Dasher without fireforming or hydroforming, so I decided to give the Norma Dasher a try. 6 BRA wasn't a thing at the time I had the barrel spun up. The longer neck of the Norma Dasher is nice compared to a standard 6 Dasher.
Only change on my chamber compared to the bullets.com reamer and chamber is going with a 0.274" neck diameter, I didn't think 0.272" neck of the stock bullets.com reamer provided adequate neck clearance for a rifle that sees field conditions (i.e. gets a bit dirty and goes longer between cleanings than a benchrest gun.) Josh @ Patriot Valley had his Norma Dasher reamers made with a 0.274" neck for the same reasons. Wade Stuteville did my first barrel with the bullets.com reamer and opened up the neck to 0.274", Josh @ PVA is doing my next barrel with his 0.274" neck reamer.
I have 600 pieces of the first batch of brass with the 0.008" thicker rim that some people had problems with in regards to extractors and shell holders. The first lot "thick rim" brass had slight issues with my AI AE and I had to modify the extractor hook as it would only extract about 50% of the time-- but my AT and AX extracts it no problem with no extractor mods. Newer batches have a thinner (standard) rim thickness to work with all shellholders and extractors, but this means less material surrounding the primer pocket which may have a negative effect on primer pocket life. Can't say for sure as I haven't tested the newer "standard rim" batches of Norma Dasher brass.
One of my 100 piece lots of brass has 9 firings on it now and the primer pockets are still really really tight. My initial load and node was 31.54 grains of Varget with a 105 Hybrid at 2910 fps. New load is 34.6gr of RL16 and a 105 hybrid at 2975fps. Quickload shows the faster RL16 load to be lower pressure (50 ksi) than the slower 31.54gr Varget load (54.3 ksi). Both Varget and RL16 are stupid accurate. Both loads are rather mild and could easily be pushed harder, but 2975fps with RL16 gets the job done for me without getting stupid on pressure.
Thought I might change over to 6 BRA, but the Norma Dasher brass is treating me very well and I'm having another Norma Dasher barrel spun up by PVA right now. Current barrel has 1800 rounds on it; it looks great in the borescope and hasn't dropped accuracy or velocity yet, but at 1800 rounds I figured it would be prudent to have a new barrel ready to go. I figure I'll keep spinning up Norma Dasher barrels until the Norma brass dies, then I may switch to Lapua brass and go 6 BRA. But with one 100 piece lot of Norma brass having 9 reloads on it and still having extremely tight primer pockets I will probably be sticking with the Norma Dasher for at least 2-3 more barrels.
All that being said, if I was starting today I'd probably go 6 BRA just for the Lapua brass. The Norma Dasher brass is treating me very well, but the Lapua brass is time tested and proven to be about the most durable stuff out there.