Well guys there are several reviews on the service, though most of those are aimed more specifically at the G2 than the G1 which is what Woot is offering.
The question is it the same as Pandora, in my way of thinking absolutely not. Though Pandora is now available for streaming from phones and even the iPod Touch, it still requres a data plan or wifi connection. Once you lose that you no longer have the ability to listen. The slacker downloads via USB or Wifi at your convenience and this is when it refreshes your channels. I do mine at night when I go to bed, I just plug it in to charge and it does the rest. I wake up the morning it has a full charged battery for about 12 to 14 hours of playback with fresh playlist.
Does it compare to sat radio, music wise in my opinion it kicks sat radios ass. SQ wise it kicks sat radios ass. You ever listening to a station and just hate what is playing, you have two choices grin and bare it or switch channels. The Slacker allows you to skip to the next song and if you really don't want to hear that song again you can ban it. It won't ever plan that song again on that channel. If you use the web interface you can even ban an artist from every playing on your station again. Imagine taking your favorite 15 or 20 artist and creating a station and if you have the premium service you can even request specific songs. You can save song for later playback sort of like the Stiletto. Now Slacker doesn't have the right to every song, so some will save and some will not. However you paying for a subscription is optional.
There is no talk, sports or news yet on Slacker, there is a couple of comedy channels. But Slacker right now is all about the music and it is every bit an equal to sat radio and in my opinion even better. I am amazed at how you can customize channels even the professionally programmed ones to your liking. If you like more hits based or more fringe tunes if you like currents or classics or somewhere in between.
This Woot deal is a good one in my opinion, though this is the older bigger model. I wish all I had ever spent on sat radio originally to get started was $50. Even if you just use it occasionally it will pay for itself, but I have a feeling once you get it and start using it, you'll find you will use it a lot more than you think.