The top strap strengthens the frame. A steel frame Remington is much stronger than a steel frame Dragoon type with no top strap. But the Dragoons are quick to take down and can be cleaned easier because after you remove the wood grips everything can be soaked and cleaned in hot soapy water.
I had a Walker Colt from Uberti and it was a monster. I loved it but I needed money and sold it. It was a Dragoon on steroids.
I also had a 1858 Remington New Army Target model in Stainless steel. I liked it better than the Walker. The Walker would reliably shoot 50 gr of 2f or 3 f. Max was 60 gr 2f. BIG BOOMER! The Remmy load was 30gr max.
My next one would be one of the Uberti or Pietta (Uberti preferably) 1858s. Why? A bit lighter and more accurate. The Walker has a 9" barrel. The Rem had an 8" bbl. Shorter barreled models are available for the Rem but not the Walker. Whichever type you get, if you get a long barreled gun, let me know. I can send you a shoulder holster for the price of the postage.
If you get a smaller Dragoon, or even a Remington type do not get a brass frame revolver. They do not last as long because of the brass frame.