Do you have a down comforter? "Down alternative"? Where did you get it? How pricey was it?

We finally settled on a duvet set (seriously-- we bought a king size a full year ago and have been sleeping with our queen comforter and duvet!). My parents offered to get us the comforter for Christmas and I just need to pick it out. But I'm overwhelmed with options-- I just want a nice, but not super fancy or expensive, warm but not super warm, comforter.

So, what do you have? Pros and cons to down vs down alternative?