Both are great rifles. Depends if you like a Lever Action or a semi auto?The Ruger Deerfield 99/44 only holds 4 rounds where the lever action has a greater capacity(10).Ruger made a 44 semi auto years ago and discontinued them. They were the Model 44 Autoloading Carbine.The first ones were called Deerslayers (1961 or 62) until Ithaca filed a suite against Ruger for Name Infringement. If you want a semi auto the Ruger is the way to go. I've never been much on lever actions but Marlin does make a fine L.A.If I'm not mistaken Marlin discontinued the 1894 back around 1984.
Ruger Redhawk