The ruger already comes with a 22" semi-heavy 5/8x24 threaded barrel and uses AR mags. That's 2 things I find more appealing about the RAP version over the Howa. Personal opinion.
i like the rugers, i was thinking of getting one in .223 just for plinking, but i built an SPR styled AR instead. when looking for guns i usually determine what accessories are available, how easy they are too get and what they will cost. i have boxes full of AR mags, so that would be a major plus for me. plus, the vids i've watched, they seem to be pretty accurate, especially for the price.