Hi Traveller!
The Start it Up is a 30 minute low impact workout - I'm sore the next day, but it hasn't taken me anywhere close to muscle failure, and it isn't like I'm near exhaustion (except for this morning). But I don't think it is meant to be really hard, rather it is to prepare you for the next two levels.
I'm going to be starting Ramp it Up soon, so I'll let you know.
I like that the moves are easy and it is very straightforward.
Although I will say that I got this program to gear myself up for things like Chelean Extreme and p90x, because from what I could gather they are harder. But what do I know
The Billy's Bootcamp (I did this once at my mothers) was much more intense than slim in six, and the resistance band was harder (which is probably why poor Billy was sitting at mom's collecting dust) and I wasn't in good enough shape to do that everyday.
Sorry for the ramble - that was a lot of words to say I'm not sure!