I have a RAB, long sleeve and wire hooded jobbie. I use it late autumn, winter and early spring for tours. I use it as soon as I'm off the bike. Down is a mission to wash all the time and degrades the insulation properties, so I avoid getting it sweaty and wear less while riding.
It rolls up to almost nothing and is very light. The model I have can wrap into it's own pocket, but I'm not so harsh and roll it up in one of those orange, mesh, kindling bags. Quicker to loft up. I love it. I've never been happier with a technical piece of clothing.
That said, I haven't made the jump to a down sleeping bag. It's always too wet and warm in the U.K. for me to be confident enough to justify a purchase.