If you dont want to drop Math, then pick 2U Mathematics, no point in doing General Math.
Only do general, if you're really not that confident with maths (you should know by now from your junior years, how well you are at maths), but still need some form of maths for your career, e.g. industrial designer or some
TAFE course that requires basic measuring. They look for at least general maths, in those types of courses.
If your heading for
uni, depends what you want to do, if you need something to 'fill up' your units, but don't really want to go towards too much trouble in studying. Then go for general.
However, if your looking at a career pathway that relies on maths heavily, I strongly suggest
Mathematics or greater. E.g. for
engineering degrees, mathematical, accounting (financial), or computer science.
Having said that, I had a friend, who started off on 2unit maths, but dropped to general in year 12, did a bridging course at uni, and now studies engineering with no troubles. (But I guess that's entirely dependent on the individual, and whether you're up for cramming most of the Maths ext1 course within 2 weeks).
Different people on here, have different performance levels for maths, but from my perspective, I found 2 unit Mathematics (advanced), to be quite a solid journey. You have to put in LOTS of time and dedicate **a lot** of effort to do well (i.e. at least band 5).
Hope that helps, feel free to pm me for more advice. Good luck with your HSC! and always keep determined!