Hello,
The workshop heaven blades are actually T10 steel, which is a Chinese water hardened steel similar to the now unavailable W1 steel that very old planes may have had. It is a fairly simple carbon steel, but being water hardened, does seem to take a sharper edge than many alloy steels we come across. It is also reasonably hard, so quite good at keeping its edge for a carbon steel. As far as A2 steel goes, I find Ron Hock irons A2 cryogenic to be the best. They seem to take a finer edge than the Veritas and at low angles. The Veritas is fine at slightly higher angles, maybe 35deg, though in milder woods normal honing are fine. These are all a little better than standard Stanly irons and such, though are much better manufactured in terms of surface finish, so easier to prep when new. Older Record laminated irons crucible cast steel are nicest of the ones original to the planes, and are worth keeping. I would never buy a standard manufacturers replacement iron though. For my money, the QS ones are about the best for price and performance. I have a few Clifton forged irons and they are good, but too expensive and now unavailable anyway. I liked to buy British at the time I got them, but in all honesty, they have no performance difference to the QS to justify being 3 times the price. I have not tried the new Cliftons, but suspect they are not much different. Cryogenic treatment of carbon steel has marginal benefit, and I would guess th QS would be indistinguishable or perhaps slightly better. I had to try Veritas PM V11 when it became available in Bailey style blades, and got one for my Record 07. I would say that it is slightly more tenacious to sharpen, but not a major effort, though it needs to be very sharp. I find 8000G water stones to be good, but less fine and the iron just does not perform well. I have not tried oilstones with it yet, because hard Arkansas and a strop to finish would be necessary IMO to get the best from this steel. When truly sharp, it is really rather good for abrasive timbers and does keep an edge considerably longer than anything else I've used. Whereas most other steels are close enough not to make a lot of difference in the longrun, PM V11 is tangibly better by leaps and bounds. But in moderate materials is not really necessary if cost is important. If you need performance in abrasive wood, though, are probably the best in terms of sharpenability and edge retention. HSS will retain its edge but is never as sharp so surfaces are not as good. These are observations I have made with my own tools, over many years of woodworking.
Mike.