Is b7 stable enough to upgrade to?

That's like going to your local bar and asking the barkeep "is this scotch too strong?" Whether you can handle 2.0b7 depends on how much you can stomach little annoying bugs that might pop up, in exchange for some new features. I would definitely try beta7 out, and if the bugs bother you, you can always downgrade.

Beta 7 is by no means rock solid... It's at the very edge of what I consider usable for daily listening. Beta 3 was a little more stable for me but it had its own issues... If you want something rock solid, stick with 1.03 and wait for the kinks to get worked out.