Why wouldn't you?

[barefootek]

It will depend a little on where you want to teach too... If SSI are big in your area, then it might be a good idea. I work in S.E. Asia, and PADI has the lion's share of the market. There are a few SSI shops about too, but it's much easier to find work as a PADI instructor. Many instructor's over here are both SSI and PADI certified. If this is route you're thinking of, then financially I think it'd be better to do a PADI IDC and then cross-over to SSI, rather than the other way round.

I am still investigating and will definitely follow this post, but I have been leaning towards going through a PADI GoPro program. I am currently going through Stress and Rescue with SSI, but I think that I will have a lot more options when looking for employment if my instructor's certification goes through PADI. If you already have a connnection with someone involved with SSI then I would go that route. They are a quality organization. But if you are just going to go through a program then it seems to me that you are limiting your options with anyone other than PADI.