Big Duke
I, like Frequent Flyer, have only used the Dyna-Nav, but have talked to some guys who have used the Kodiak system. What I have got out of my conversations is that they are quite similar. The major difference being that you, as the pilot don't have as much control over what you can see on the Kodiak. With the Kodiak coordinator sends you a mission in the order he wants you to carry out that mission, you are then obligated to that mission as set up unless it is changed by the coordinator. The difference with the Dyna-Nav is that the coordinator sends you all of the information you need to do the job. You then organize with him/her what he/she wants done and in what order. This gives you the opportunity to add your input to make things easier and in some cases safer for yourself. All the coordinator is woried about is getting the job done efficiently, how you do it is up to you with the Dyna-Nav.
Consider some situations. You are picking bags with a bag picker. You can lift, lets say 4 bags from an open area but can only vertical out of tall trees with 3. The coordinator asks you to pick a certain rack of 4, but the second bag is the only one in a clearing. With the Dyna-Nav you have the option to pick bags 1, 3 & 4 then go back to bag 2 so you can get that rack of 4. From what I have heard you don't have that option with the Kodiac. Another instance is that of having the option of which direction you pick or lay out in. It is nice to be able to keep yourself as close to into wind as possible and with the Dyna-Nav you have the option of changing direction without a new mission from the coordinator.
I have heard guys say that the Kodiak reduces your workload because you just follow what it tells you to do, but I like having options. I started using the Dyna-Nav with 400 hrs total time (scary hey), but had no problems adapting so I think ease of use and pilot workload isn't much of a factor if a 400 hr pilot can use it. After a couple of years of working seismic the Dyna-Nav is all I have experienced and I have learned to work through some of its excentricities and now appreciate what a good tool it is. Hope this helps. Sorry but I don't have any drill move experience so I am no help there.
TB