What are your opinions on 35S and is it possible to change my MOS before basic starts?

You can always back out before you ship. You could renegotiate your contract or be a DEP loss.

That being said, that is a pretty great way to make your recruiter hate you. Also, just because you want that job, doesn't mean there is a class seat open for it. Or the next open class seat might not be for a year. The longer the MOS, and the more low density it is, the smaller and less frequently they run classes. That means if you back out now, there may be no seat for the job you want, or you might not ship for another year.

I am a 35S and can give you all the information you need. You can only get a few duty stations with this job. Colorado, Maryland, Hawaii, Georgia, and S. Korea. HOWEVER, if tactical work is what you desire then you want to make sure you go airborne. this will open up pretty much any duty station for you and boat loads of awesome tactical work. The work that Sierra's do overseas is really cool and not many people get the chance to do that. Not even overpuplated "grunt" MOS's.

Don't expect a lot of physical work as a 35S. You're needed for your knowledge, not your strength when you're doing your every day job. However, deployment may be a different story with this MOS considering all of the heavy equipment you may have to carry. You will get a TS/SCI and the AIT is fairly short in Pensacola, Fl. The contracts are shorter than most other Intel contracts which allows you to get out or reclass sooner than someone like a 35N or 35P. There is money to be made after the army with this job and there are assignments that can be physical with this job, but you have to make yourself stand out for either of these to happen. Nothing will be given to you in the army. If you want to take a swing at the more physical part of the job, make sure you have a GUARANTEED SLOT FOR AIRBORNE IN YOUR CONTRACT.