I have owned several SUUNTOs over the years
all 3 of my watches have had the compass fail on them, once even just a few months after a warranty fix
They have worked flawlessly otherwise
you need to set "ref" barometric pressure to your current altitude which you need to get from some other source with current barometric pressure
I stopped being anal and caliberating mine all the time and the alti works great, as far as measuring change, but it can be off by a bit as 'sea level' is relative to the weather systems- meaning you can use it as alti or baro not both at the same time, tho while camping its more important to see if baro has been rising or dropping
after the new-ness of the device wears off, its a functional outdoors tool, but dont rely on it for uber accurate altitude readings unless you caliberate it to sea level
the user manual is good, just get really stoned before you try reading it..