I'm not serving but my husband is. His cap badge is the one you're interested in. So, bearing in mind that any info I give will be from an outsider's perspective, here goes.
A career in that field can be interesting and varied - my husband has done all sorts in his time - but it is not a stable form of life for a family, although it is possible to manage it perfectly well. It all comes down to how you and your partner/husband operate as a couple and as parents once the sproglets appear.
We got married six months after he finished RMAS and in the six years following that, we moved home six times. Postings are, in theory, meant to be for two years (two and a half/three years for Lt Col and above) but the needs of the service mean that you can be short-toured and moved early. In those six years, he did two operational tours (Kosovo and Afghanistan). We then had our first child and we opted to buy our own home and settle somewhere. In the six, almost seven, years since our eldest was born, he's had he's had four postings and two operational tours (Afghanistan - twice). We managed weekly commuting for a while but then we had to settle for our current routine - he comes home for the weekend every two to three weeks, depending on the demands of his current posting.
The Army is trying to move towards a structure that would allow personnel to remain in one location and change jobs within that location - however, that is designed around the infantry and those who are trickle-posted (like the Corps) would still have to move fairly frequently.
I won't pretend that commuting is easy, but it works for us just now. We have three children aged 6, 4 and 2 and we manage a decent quality of family life.
From a career point of view, my husband loves his job and has done very well. He has done all sorts of jobs, not all corps-related, and the one he says was his favourite was not his specialism at all! We've lived all over the place, although never overseas, and we've loved most of it. He still has sixteen years left to serve, so who knows where it will take us next.
Pomotion prospects ca be good - he left RMAS in 1999 and became a Lt Col in 2011, so rapid promotion is possible.
However, it is possible if you are ambitious and prepared to sacrifice other things to make it work. We take the view that I maintain things and work hard on the domestic front to allow my husband to concentrate on his career - between us we provide stability for our children and a secure future.
One thing I have learnt as a Corps wife is that lots of people want to join the corps (approximately half of any intake at RMAS register an interest during the course) but they select relatively few per year (9-12 cadets, roughly).
It sounds as though you're at the beginning of the road - going to the careers office for advice - you need to get selected for AOSB, selected for RMAS and then selected for the Corps - a fair few hurdles yet, but by no means impossible.
I'm sure you know this, but the cut-off age for entrance to RMAS is before your 26th birthday, so if that's looming on the horizon, you need to take action quickly.