If you have a reputable degree and have no screw-ups, you should be able to attain the rank of LTC by the time you retire, and your salary should be around there or more.

Do note that should you at anytime wish to switch, the jump to private or even to any other public agencies will be very hard. The working experience you've accumulated will be considered almost nil, unless you've the rank of at least Major when you wish to jump ship. Even then it's hard to enter any specialist role, but you can try those generalists position.

Stability wise I'm not very sure about it now, as its all on contract basis subject to renewal based on work performance. And it'll be hard to climb up the ranks as there's too many scholars in SAF (even after excluding those overseas merit scholars).