Hi Griff,
Welcome to the MJ club. This is great software. A few enhancement and fixes will make it a perfect software.
I've ripped a few hundred CDs, and also re-rip some of my favorite CDs afer I finally switch completely to MJ- from Realone (Rip off: I've declined subscription, and they still charge you, and send you software that you decline to buy) and MusicMatch (still a good jukebox).
But MJ is much more fun. The track visualization uses HTML, and you can design your own. Very fun. Can also add visualization.
As for the format, I use MP3. Like many MJ users, I choose VBR format. I play it over a high-end HiFi system, and it sound very good.
My recommendation if you enjoy listening a lot of CDs:
a) Get a very large harddisk. A 120GB disk cost $250 USD only
b) Get a very good sound card. I use the CREATIVE Extigy, and it is perfect.
c) Rip with the best quality. The wait is worth it. The disk space used is worth it.