TA work would def let you get a feel for the job, but yes, the course would take nearly as long as a teaching degree. Alternatively, you could volunteer at a school. You could get a feel for different age groups and choose hours that suit you. It also looks great when you're doing your prac work. Every student I came across who did above what was required was offered work (from TA stuff through to supply teaching and long term contracts).

TA work is lower paid (unless you work out your hourly pay rate as a teacher including all the overtime - wasn't pretty!), likely to be shorter hours (yes, 2-3hrs/day isn't uncommon), but you just walk out at the end of the day. With teaching, you are likely to be in early, out late, working at night and on weekends. There's marking, reports, extra-curricular activities, school camps etc. It's a position with lots of responsibility and you'll likely come into conflict with students, parents, other teachers, specialists, admin at some point or another. It's also extremely rewarding and I miss it every day! Having said this, I was considering doing TA work before I fell pregnant because of the shorter hours and decreased responsibility.

Teaching is very different now to what it was. In the past decade, technology has made a huge impact. It is incorporated into all learning areas. The national curriculum is causing huge changes in some learning areas, and in some states more than others. Student management (behaviour) is a huge chunk of your day, and you will need to be able to deal with a huge range of student needs/issues.

I hope all this helps in making your choice.