I just bought the DG03 myself and struggled with the same decision. I ended up with the Hollis. Here's my thought process:
Hollis:
-Moderately conservative Pelagic Z+ algorithm, like Oceanic, et al.; can be adjusted to be more conservative
-Air integrated, if you (eventually) want it. Up to 3 transmitters.
-Track 3 independent gas mixes
-Gauge mode
-DiveGearExpress has a good deal going right now, $249 + cost of DSS bungee and cable
-User replaceable Battery
-Audible and light alarms
Suunto:
-More conservative RGBM algorithm
-Up to 50% nitrox, only 1 gas mix at a time as far as I can tell
-User replaceable battery
-$249 at LeisurePro, plus cost of DSS bungee and cable
-Audible alarms
After looking at it, the only place where the two came apart spec-wise was the air integration, multiple gas mixes and gauge mode availability. The rest is based on personal preference (algorithm, layout, etc.). I went with the Hollis because I figured I might want to try air integration down the road, and I liked the idea of being able to track multiple mixes eventually.
So far I've done three dives (one square, two deep multi-level) on the computer; each time the computer has matched the safety stops/bottom time limits we had planned pre-dive. I will say that the initial setup can be a bit counter-intuitive, but in the water the computer presents its data well and is easy to read. It works perfectly fine with Subsurface on my Mac. I am happy with my purchase. Also, the DSS bungee is worlds better than the standard boot.