How can I choose between Shazam and SoundHound? I want a Music ID app, I have tried both Shazam and SoundHound which were good. They both have a limit of 5 songs, and cost $5 to upgrade to unlimited. Before purchasing one of them, I want to make sure I'm making the right choice. What are the advantages/disadvantages of each one?

Are there any other competing apps I should consider?

Update: I used SoundHound's old name, Midomi, accidentally.
I would pick a handful of songs that are of the type of music you like and see how each one does at identifying them.  Also consider how long it takes each one to get you your results.  Also if you buy music through a particular service, consider the app's ability to interface easily with that service.  The other big thing to consider would be startup time of the app, since you want to be able to tag a song before it ends!