I have the Nemo Titanium and my feeling is that it is superior to the D3 in all areas except for the storing of profiles. I checked the Apneist manual and it looks like they improved this area. Sampling rate for profiles is now 1s - same as D3, but the Nemo has a much faster sensor, giving you more accuracy. Also the profiles for freedive can now be viewed on the watch (before only after download to computer). Only thing that is still annoying is that it stores the profiles only of the last session.
If you can have it at a decent price, than I would surely get the Apneist. Depth interval alarm is the way to go
After checking the D4, I was not really thrilled about the upgrades, at least I think the sensor got better.
