Yeah Butch, the old rules of Stihl numbering don't hold anymore.
If you want the 440 (if you can find one in a store somehwere) 460 or 660, get them now. They'll be gone in a year or two, in favor the new 441 design on all of those motors-461/661 on the way.
It's the newer, cleaner, quieter, smoother running saws.....note I didn't say "better." They are good and well-designed, but the older free-breathing saws are hard to beat.
Dave said in a few years people won't even know what it was like to run a 440. He's right. Hell even within the 044 to 440 there were significant differences. The original 044 ran like a raped ape compared to the choked down 440 of later years.