I've only done No More Trouble Zones, 30 Day Shred, and Banish Fat Boost Metabolism, but I have liked each of those videos. Even though Jillian uses weights in some of her videos, I personally use them as cardio videos because the workouts definitely get my heart rate up there, but the weights used are so light (3 to 8 lbs, depending) that I don't think one can really build muscle with that type of workout (not like you would in STS or some of Cathe's weight videos).
You can try a lot of Jillian's stuff out through Netflix, or on occasion I've seen her new releases at Costco for around $8 or $9.