I have one of these installed in one of my v4 uBITX. It works very well. As others have said, you will need to be careful with earphones, as it can generate a very high sound level.
I have not used the ATT and IF Shift much, but do believe that the settings are not saved after shutting down the uBITX. It would be nice, however, that would require a lot of reads and writes to the EEPROM that could cause an early failure. The buttons are on the main screen. There are sliders for each of them, however they are small. Maybe just modifying the Nextion screen to enlarge them would work for you.
Most hams use a stylus to operate the small touch screen. Plastic with a rounded and smooth tip so that you do not scratch the screen.