First thing that comes to mind is I cannot define my own tanks. In Suunto's app I can put "X8-119" in the cylinder list and specify capacity and pressure. In SmarTrak I have a pre-set list of tanks to choose from. I can change their specs, but not their names. So I have to remember that the tank listed as a 120 cu ft is actually my HP 119.
If there is a way to edit the name, I missed it despite looking for it, which is more evidence that it is crummy.
Adding dive sites is cumbersome. Awkward interface.
I can't have my graph show heart rate AND temp AND workload. It's one extra bit of data at a time. The Suunto app let you show pressure and temperature at the same time as I recall. I can't even find a way to show gas consumption on the SmarTrak dive profile at all--just the "workload" line.
It gets the job done, but only a mother could love it. Perhaps it's the case of the devil you know. I have 84 dives on the Suunto app and a couple on the Uwatec app.
I am interested in that German dive log app, but it doesn't do SAC calculations per the faq. Yeah I can do them myself but I bought a computer so I don't HAVE to do math any more, nor scrawl notes on pages myself.