My Pandora One subscription was up, and not having choice was a little annoying.  So I decided to give the new and the old a try again and see what worked.  Here's what I tried and I learned:

Napster - song selection was good, quality was terrible.  After listening to Pandora for a year at 192 kbps, I was disappointed with the quality here.

Rhapsody - song selection was great, again quality was terrible.  Rhapsody iPhone app was also decent.

GrooveShark - song selection was poor

Rdio - seemed to be OK, song selection was Ok, app crashed too often

MOG - quality was great, app was terrible.  Crashed more often than Rdio's

Google Music Beta/Amazon Cloud Player - both were good, Amazon crashed occasionally, but both only gave me access to tunes in my library.  I am a music junkie and wanted access to more.

Spotify - new to the US and have been trying the free version for a little over a month.  Free version is good, but without iPhone and offline support, it's a pain.  But with the premium version, I found a winner.  Quality, song selection, local integration, application speed, device support is all good.  I have had a few crashes and glitches with the iPhone app, but everything else seems to be great. 

Not going to be stopping my use of Pandora for music discovery - it's great and has turned me on to many artists.  But, I am going to be giving Spotify premium a longer term trial because I like to unlimited skips and to choose to listen to an album if I want. :)