kysingleshot.
All of what Mitch said, except, unless you buy a used gun or and older new one that hasn't sold yet, there is no longer an Ultra Comp rifle. the 30-06 is now called the Ultra Hunter and it does NOT have a compensated barrel. They used to but discontinued that line.
I have standard Handi rifles and an Ultra and there is no difference except looks. If you want a hunting rifle and not gonna worry about scratching it, get the Handi, otherwise go the Ultra. Some Ultra's do offer a slightly longer barrel, so look closely for what you want.
The Ultra does not accept any barrel the Handi does not, ALL SB-2 receivers accept the same barrels, including the Buffalo Classic and the Target model 38-55.