Taking things back online, let's search for a track. Wi-Fi off, though, so we could see it working over a typically poor O2 data connection. Songs were pretty slow to load over Edge, and we had to give them time to load as they lurched and paused quite badly.
However, when on 3G, there was no problem and very little inter-track latency. Sound quality is also excellent.
The Search is self-explanatory, while you can flick through the Tracks and Albums tabs when you have typed in your search term. Once you've found your album, you can add it to a playlist, shuffle it or play your choice of track.
This is what the tracks bit looks like. In our mind there should be a third tab here, for artist – not sure why it isn't included already, but hey. As with the desktop app, navigating around can be a little tricky if you want to search by artist and browse through their albums. Spotify's search is track-orientated rather than artist-orientated. This was a little frustrating for us, but probably not so much for others.
Here's the main play screen and, below it, the information screen, enabling you to browse the album (useful if you'd just searched for a specific track) and add it to your playlist.
Presumably this would be where any buy links would be – that must be a plan for Spotify, but since it has a deal with 7Digital, we're not sure how that would (or, most likely, wouldn't) work out with Apple.
Oh and by the way, unlike the desktop version of Spotify, the iPhone app doesn't sync details of your played tracks to Last.fm.