I've done 27 dives with the DG03, all but a few of these non-deco dives. Most of my dives are between 35 and 50 meters using two gases, and I used a third gas during TEC50 training, just because it was part of the course and the computer functioned perfectly. handling the three gases. Setting the mix and switching between them is quite straightforward (once you understand the damn manual, more on that later).
I want to like the Hollis, as it's an inexpensive three gas computer, but I'm finding it hard to do so. After 5 dives the screen malfunctioned (cosmetic issue - some of the non-essential information doesn't get displayed) and after 26 dives (about 45 hours total diving) I now have a low battery issue. It should last 300 hours, not 45!
I recognize I may just had a bad one, and I do feel confident that Hollis will honor their warranty, but I'm in Bali, so getting service here for it is simply not possible.
The two real complaints I have are the manual and the interface. The manual is just awful. I mean awful. Download it and see for yourself. This thing breaks records for crapness.
The bigger complaint is that the interface has some real challenges. It IS a confusing computer to dive with.
The display shows far too much useless information (the day of the week and the time, always helpful at 45meters!!!!) and hides the really important stuff like max depth and RUNTIME.
Let me say that again. RUNTIME is not displayed on the main screen, You have to press two buttons to access this information.
This makes following a dive plan just that bit more challenging because you have to keep pressing the damn buttons to see the runtime.
Most of my dives are deco dives and as soon as you go into deco, the DG03 tries to get you to make your first stop at 9m. That's far too big a gap from 45m, so you NEED tables to plan the dive and HAVE to dive the plan with this computer. And for that you NEED the runtime!!
Conservatism-wise it runs at the same level as V-Planner on conservative level 5, so it is conservative, but I can't fault that.
So, overall, yes I like that it is an inexpensive computer with some good functionality, but there is scope for improvement by Hollis. I will keep using this one until it dies, but I probably would not buy another.
Again, to be fair, I am using this in a Technical environment, it's not really quite up to it, but it does work, and I have to give it credit for that - It's not a $1500 Liquivision, but it does do the job where many low priced computers would not be able to.
My feeling is that this is good tool for Open Water Divers moving into Tec or advanced diving with multiple tanks/gases, but once you start to do more dives, you will outgrow it. Certainly it beats many of the other computers out there.
Just my 2c. Hope it helps.