Hi Nancy,
I do use both apps:
iLife - that is a very conveneint combo of products; everything is integrated; using every single app as it is meant for, it works like charm; iDVD, esp. the new one in iLife05, has terrific options (moving menus) or, some nice features to create very simple looking video-dvds.
iMovie is a very basic, but easy to handle edit app; I do own FinalCutExpress for more elaborated projects (or just parts! I use fCE for special effects, import them into iM)
iDVD is dvd authoring "suite"; complex menus/structures; you can "imitate" different language versions of a project on one dvd (not really different audioo tracks, but like...); the new "structure" view makes you feel like working with DVDSP...
Toast7: VERY different! this is NOT a dvd authoring app, but some "burner" (in many meanings); there is just one single menu to choose from; no individual menu design possible; but zillions of options to create any "burned" media, from data (spanning feature!=> dividing BIG data onto many discs)), all kind of formats (PC, ISO, udf
); converting into different codecs; latest feature: video into divx-codec
speed? never heard of a comparison of both products, wouldn't make much sense, iDVD offers complex menus = time, Toast not; Toast offer codecs, iDVD cannot create....
yepp, you can "jump" to vers. 7 directly...
summary:
doing video => iM+iDVD
doing "burning" => Toast 😉