Spotify or Rdio?

First of all let me start off by saying that I've never seen the appeal of cloud based music providers in the past. I've never had the opportunity, nor the motivation to really use them since my job has me driving a lot, I usually just listen to the radio. I thought I knew what they were about and the service they provided - boy was I wrong...

Having read a RT on twitter earlier about a new version of Rdio (totally unheard of to me) I decided to give it a go and take the 7 day free trial (since I got a new CD player for my car yesterday with a 'Made for iPhone' front USB port). Rdio is gorgeous! After that I found they had a Mac app, I downloaded that as well, also beautiful. The two apps played seamlessly with one another. I'm not getting into syncing albums to mobile and offline mode, etc - I'm sure you guys know about these features, but for pure UX, for me, it's been incredible.

After these 7 days I'll give Spotify's trial a go. Although first impressions leave me pessimistic about Spotify and how plain ugly it looks compared to Rdio and I find the design of something quite important.

Both services offer the unlimited mobile package for £9.99p/m.

How do you guys feel about which service is better? Bigger and better catalogue, etc? And which service plays nicer with iTunes and iOS?

Also, if I pay the monthly subscription, can I use it on multiple devices on the same account? i.e. my iPhone and my girlfriends iPhone.