I think the Belkin microphone is/was pretty good. I bought it for the iPhone but the dog chewed it!
The only problem with the xeno canto site and a couple of apps linked to it that I have found is connectivity. In the mountains and in places without phone reception it, and they, don't work...
One app that intrigues me is the one that recognises bird calls. I wish I had had it in Portugal last week. The differences in calls between here and Portugal are noticeable as are the call differences between here and the UK. It takes a little bit of time to get your ear in. Black Redstart definitely had a different chirp to the one I'm used too. I heard a Sylvia which I thought was Subalpine (even sounded similar to one on xeno canto - which I played) but I wasn't confident enough in 'foreign' surroundings...
When I first arrived in France I spent a long time chasing Blackcaps buried in bushes until I got used to their dialect. Where I live in the mountains even the Treecreeper has a different dialect between valleys!