Like Graybeard said....I had a Rossi 20in 45 colt years back, it was a nice little rifle. But...I figured the 24in oct. barrel would be better, (I like the look and have always been a sucker for a longer barrel)so I sold the 20in, bought the 24, finally got it to shoot after much work. (nothing to do with barrel lgth) and now after a few years of ownership, I'm trading it to a friend who has a 20in in stainless and wants the 24 in blue. I like the looks of the 24in, but it's not as "handy" as the 20in and it is a bit barrel heavy. I think the 20in will be a better saddle gun, and it will match my stainless BBH. If the oct. barrel is your thing they also make that in the 20in now. Pick either one, pretty good little rifles.
Post script: Actually the reason I decided to trade was I've been shooting my Wifes 20in 357mag lately, realized I really like the shorter rifle MUCH better.