The Sky Safari observing list feature allows for the recording of observing notes, incl. scope and eyepiece details, seeing, and transparency. That's what I use (on the iPad) to keep log.
Unfortunately, the Sky Safari versions for Mac, iPad, and iPhone (all of which I use) don't sync their observing lists and notes yet via iCloud or some such, but Bill Tschumy recently told me it's high on their to-do list.
For what it's worth - I'm using the mid-level SkySafari 4 Plus (on Android), and it has the Observation Diary feature as well. I don't think the lowest cost basic version supports this feature.
There's a detailed summary of the different versions here: