Good metal tone to start with

yes, the noisegate it is perfectly usable. Another good similar amp to try is the Blackstar Id Core
yes , thats the second option to me is the blackstar id60 tvp-h , the only inconvinent is the noise gate it has 3 options off ,low and agressiv other than that i think its good . boss katana head has too much built in effect in it , power soak , internel speaker,....
blackstar has the tvp feature wich is a nice touch from blackstar.