I've looked at eBird, in the past and again now, but it doesn't work for me. It does not record altitude. The whole checklist / hotspot thing is complete gobbledygook - I see a bird, I identify it, I want to record its location (including altitude), behaviour, maybe other notes, and all very quickly, often offline. I can't be bothered with all the site searching it does. It doesn't use IOC taxonomy. And then I can't get to see my own data except via eBird's servers. The observations are mine (my skills, my time, my expense getting it), not theirs, and I don't expect to have to rely on their goodwill to see it again. BirdTrack seems to be similar, but I have even less experience of that.
I have been trying out Birdlasser, and it is good, very good. In particular, it does record altitude, and I can download the data myself (and upload to eBird were I to so choose). Its species lists are built in, and global coverage is not (yet) complete, but the folks there seem willing to add lists on request. They also answer email.
Talking of which, Stevens Creek have not replied to me. My problem with Birdwatcher's Diary arose while I was in the Azores, and my suspicion was that it was something to do with a recent iOS update (I'm not sure exactly when my last successful use of BD's archive facility was in relation to when I updated the iOS). However, I am now sitting in Lisbon airport on the way home and BD's archive is working again, nothing else changed. I find it hard to believe that there is something quirky with the internet connections on the Azores (which was both 4G and WiFi at my end) which caused the problem, but this is now near or at the top of the list of my suspicions.
So ... it seems that the world is getting a bit short of decent independent listing apps. Stevens Creek are not exactly responsive. Bird Journal (as noted in another thread) seems to be going (or gone) the same way. Birdlasser is looking good as we speak. There isn't much else that I can see. Is it all going to end up with birders only able to collect data the way eBird wants it, for better or worse? And what, exactly, is the problem about recording altitude? The GPS gathers the data anyway - it is just a matter of outputting it. It is surely a more useful piece of field data than recording time to the nearest second.
Keith