I have been veneer (many synonyms) grafting Japanese maples at work, a lot of them. I purchased the three knives pictured on amazon. Among the two Japanese blades I grew to prefer the thinner blade with brass handle because of it’s thinness. On a whim, I tried the Mora (didn’t get for grafting) and stopped using the Japanese blades -the blade is longer, just as sharp, and handle has more control.
Blade length is important because a push cut is not as clean or precise as a sliding cut -I’ve heard this from others as well, definitely agree.
Then, last week I forgot my tools at home and bought three $1.50 extending break-away-blade razor knives from the dollar store. 127 more maples later I have not went back to my true “knives”.
Whatever route you go, as mentioned above, sharp is the most important factor regardless of the specific tool. That said, the Mora and Japanese blades are very easy to sharpen relative to other types grafting blades.