Hiromoto is a fairly large manufacturer. Hiromoto-san seems to be aiming for the niche of "a lot of features for the money."
The AS and G no. 3 share the same handle, same fit and finish and same blade geometry. The blade construction and alloys used are quite different.
Generally speaking thy share good geometry, although as soon as you have the skills you'll want to do some thinning. Also, edge asymmetry from the factory is variable. Over the years the knives seem to have become more asymmetric. Any given knife will be right handed with the bevels set at around 15* on both sides -- unless reprofiled. But the knives can run anywhere from 80/20 to 60/40 -- that's a lot variance.
To my mind, this inconsistency is typical of Hiromoto's general fit and finish. These are both high value knives in terms of raw materials and the way the blades are put together, and something's got to give. F&F can be a little irregular in terms of the handle scales being absolutely flat and tight to the tang, finish on the spine and choil, and the odd grind mark. Also, the heel, right at the chin can be a little thick. But the presence of anhy and all of these falls under the rubric of "not always." Sometimes the knives are perfect.
I've mentioned this several times but it bears repeating, the handles are on the slender side. Depending on your grip, and/or hand size, this can be an absolute disqualification.
The AS is a san-mai knife with a soft stainless (420J2, I think) jigane (supporting metal) and an Aogami Super hagane (edge and core steel). Aogami Super is a very special, high-carbon steel from Hitachi made at their Yasugi plant. Many people consider it the best knife steel in the world. I don't believe there actually is a single"best," but AS is in the select group at the top of the heap in almost every knife category.
However, it is not an easy steel for a manufacturer to work. Consequently, you almost see it in either kasumi or san-mai construction, in other words as the hagane (edge/core) part of a laminate. This is because the supporting layers (jigane) prevent the knife from cracking, breaking, or remaining permanently bent. The jigane also makes it significantly easier for the maker to drill and grind the knife -- in much the same way tape or sticky paper help with plastic working.
No question Hiromoto does an excellent job making a san-mai, AS blade. It's remarkable they can sell it at the price. One question still unadressed is "what does san-mai do for the owner." The answer is: Except for corrosion, not very much.
Note: Personally, I much prefer "single steel knives" over san-mai for very subtle differences in feel which very few users will notice. So, if my general dislike of san-mai construction bleeds through just ignore it. Take the knife on its merits.
That said, the knife itself is very good, but not outstanding in any category except in edge holding which is excellent. Otherwise, edge taking in terms of absolute sharpness and ease of sharpening are very good. The knife resists both wear and deformation. If the edge is profiled to adequate symmetry the AS can be tuned up on a rod hone. You'll want to use something very fine or smooth textured, and steel with a soft touch. You'll also want to bear in mind that you don't want to push AS around too much.
Although it's high-carbon, the AS is not particularly prone to corrosion at the edge. People who worry about what special or extra care the Hiromoto AS requires worry too much. You'll want to rinse and wipe the knife after every use, as opposed to leaving it sitting around with food on it -- but that's true of any good knife. Yes, the edge will darken and oxidize between sharpenings but the stain comes off easily, immediately and completely with sharpening or steeling. There is simply no reason to force a patina or do extra scouring.
The G no. 3 is made with (wait for it) G no. 3 (aka Hitachi's ginsanko 3 aka G3). G3, along with AEB-L (aka 13C26), and VG-10 is one of the "wonder" all around knife stainless steels. The performance characteristics of the steel, including price, are extremely well balanced. Hiromoto construction doesn't get in the way of any of them either. It's an excellent balance of edge taking, edge holding, and edge stability.
The G3 is a "single steel" knife. While not unheard of, it's not exactly typical for the price range. So again, good value. Compared to the AS, the G3 takes as good an edge, but takes it more easily. It wears slightly but not significantly faster and given equal edged geometry is more subject to deformation. Again depending on edge symmetry, it is an easier and better candidate for steeling. All things considered, I actually prefer the G3.
We owned a few AS knives (including 27cm and 24cm gyutos) a couple of years ago. They were very nice indeed, but not nice enough to push the old Sabatiers out of the block. True for Linda (my wife, who has decent intuitive skills and knidly allows me to sharpen for her), too. In fact, when I told her I was thinking of giving away some of our knives her response was "not MY Sabatiers. Apparently I'd given them to her without realizing it. Go figure.