Hi I was a SAF sniper PC during my NSF days. I'm not sure if you
are dead serious about signing on as a snipper. My thoughts
are
1. Yes, training is tough and so is the selection for sniper
course. For NSF, it's more like they choose you rather than you
choose to go.
Once you are in, it's very fun to go for range and live firing. Bn
/ Bde / Div level exercises are fun too, the only problem with the
later is that there are way to few two-sided exercises. In camp,
sniper life is good ... very good indeed 
2. As for signing on as a regular (non commission officer), i feel
that your army career is limited. You CANNOT stay as a sniper sgt
for long. There are not many sniper regulars out that, most are
"stuck" in sniper training wing (like a "sniper school"), converted
to ops spec (S3 branch) or into the line units as PS, CSM etc.
During my time, sniper platoon sgts were all regulars but now they
are all replace by NSFs.
3. As for signing on as a regular (commission officer), you will
start off in BMT, OCS and follow by sniper school. That will be
more than 1 year combined. As with all regulars, your PC appt will
usually last for a year or two, than you will likely have to move
on to other non sniper appointments (unless you got backed back to
sniper school). That's the end of your sniper stint. Sniper PC is a
appointment not a vocation.
If you really like to be a professional sniper for a career you may
need to join SOF or some similar outfit. Of course that's another
story all together.
