What's so special about disco
Okay - this is a really difficult question to answer, but I'll answer it as best I can.
I want to start by saying that Disco is NOT a feature-for-feature replacement for Toast. It is, however, a $30 does-most-of-what-Toast-does disc burner. I find it's interface to be minimal, simple, and easy to use. I can get into and out of Disco much quicker than I ever could with Toast. The smoke feature of Disco, the one that people are always yakking about, is a fun feature, but ultimately nothing more than a distraction while you burn a disc.
The real sell-points for Disco are Discography and Spandex. Disco keeps a list (similar to a playlist) of all your burn sessions so you can reburn them later if you'd like, or if you just want to see when you burned those files. Spandex is a feature that will span your data (will not span a single file) across multiple discs until it can burn everything. That is, if you put 900MB of data into Disco when you're burning to a CDR, it will tell you the burn will require 2 discs, and it will split the files up the best way it can.
If you need the more advanced features of Toast (DVD-shrinking being a big one), then you'll probably want to shell out the extra $70 for Toast 8. If all you need is something that'll burn CDs and DVDs (video or data), then you might consider Disco as an option.
Give the trial a look - you get 7 free burns before you have to pay for it, if you don't like it, uninstall it and go back to Toast.
And just in case you missed it above, here's the link to
Disco.