Personally, I feel there is no comparison. The Diamondback is not the "junior Python" some seem to think it is. The ones I remember when they were still being made were pretty mediocre. The action is gritty and the accuracy is poor.
While it looks flashy on the outside, performance-wise it is closer to a Charter Arms or Harrington & Richardson.
But, if you want a finely tuned .22 revolver that possesses match grade accuracy and you want to see the "prancing pony" on the frame in deeply polished blue steel, I highly recommend the Colt Officer's Model Target or Officer's Model Match. The latter was made until the late 60s or so, the former dates back before WWII. Another nice one, often overlooked, is the old Colt Police Positive Target. It's built on the smaller Colt DA frame, but it shoots great!
These were made when Colt still employed highly skilled workers who knew how to build and tune a fine revolver.
Be aware that the early "Target" models have a windage adjustable rear sight and an elevation adjustable front sight. That is, unless you run into a rare King's Gunworks modified Colt.
The later "Match" version has a conventional Elliason target style fully adjustable rear sight.
My brother owned a pre-war Colt Officers model Target. He bought it from a collector in unfired condition. We fixed that right away! It was the finest shooting .22 revolver I have ever shot, bar none. It was also absolutely beautiful.
All if this, of course, is just personal opinion.
