Is there a Sirius Stiletto that is actually 100% portable?

I have never actually owned a Stiletto but from what I hear on reviews none of them are actually portable. The first models were able to record 100 hours or so of the radio but it wasn't actually live. I think the new one which is Stiletto 2 claims to be portable but some reviews say that it won't work in a car or indoors. Is this true?