Agree with all the above and will add a few thoughts.
SHARP, SHARP, SHARP! Yes like everyone else said before it has to be sharp, and I will add if your knife is not sharp your wrist will see more work and strain because you will have to work harder.
So edge retention is very important, but of great importance to you because as the edge dulls as all will with use it will make you put more force into that wrist.
Still there are many other important aspects you need to consider, and first is budget. It would do you no good if you get great recommendations for knives you can not afford, so please advise on a budget as it will help to get things pointed in the right direction.
Now I guess we could assume that being you are looking at shun you are looking to spend around that amount etc, but even if that is not accurate do not worry because the "entry level" recommendation is so much sharper and superior to most of the popular western knives many have used in the past that you will likely be smiling ear to ear like so many others have in the past.
Without more history it is hard to be sure of your exact experience etc but what these guys consider entry level is most often considered "awesome " or "frigging sharp" to most everyone else. Now just think about what a knife that is revelled or loved by these guys must be like
Seriously it is hard to explain, but I like my "entry level" Japanese Knives so much more than the popular Henckels etc I had in the past its not funny, but it is hard to comprehend the difference until you experience it, and honestly even more difficult to explain the difference between entry level and the higher quality knives until you have something to compare with yourself.
I am sure any of the others as well as myself would be happy to try and help you make sense of it all, but I think it would help you more once we know your experience and expectations in more detail.
This is hard to explain in writing but basically my $49 entry level Tojiro santoku requires very little effort to cut most things and will pretty much just cut through a tomato by its own weight when fully sharp (something I never was able to say about my previous German knives and they were heavier lol) but my almost $300 konosuke HD gyuto does it so much more gracefully and with even less effort, and will stay sharp enough to continue doing it that much longer. Hope that makes sense and helps! It took me a while to get a grasp on the idea before actually being able to handle them (and that required owning them) but it was a whole lot easier to appreciate the difference once I did get to.
The harder part is in figuring if the added benefits are worth the pretty large added expense for you.