I guess it's personal preference. ASUS has good panels. IPS has been capable of 1ms for quite a while now.
The reason why the ROG is cheaper is because it doesn't seem to be made anymore, so prices drop after a while. The TUF monitor is a little bit bigger, is 280Hz instead of 240Hz and has an HDR400 certification, but HDR400 is mostly a joke. The only other things are that the TUF monitor uses less power (20W vs 32W) and the monitor stand is more conventional. The ROG stand could be a problem in some cases.