invisiblehand

As a "hopeful" casual rider, I would not spend a lot of money on your first bike. You did not write much regarding your expectations, but it sounds like you will almost always be on roads and multi-user paths instead of single-tracking. So a MTB is way overkill and almost certainly much slower for the type of riding described.

I have ridden the Speed and Mu series. I find the Mu series a much stiffer bike which is probably a good thing since you are on the heavier side. But I think that the Mu SL is more than you need. In my experience, new riders usually change their preferences quickly and often get a different bike that suites them better. Consequently, I think that you are better off getting a lower-end bike that you can use in the future as a secondary "beater" bike.

If you are motivated by the Dahon models, I would test ride the Speed P8 and Mu P8 and save the money for accessories like a rear rack and some bags, spare tubes, patch kits, emergency tools, and so on. Ask about swapping the Mu P8 Marathon Racers to Big Apples which is better suited for casual riding. These bikes also appear to have more "normal" wheels which are generally considered better for traveling since they are more robust and easier to adjust/fix.

Take a peek at Jay Gaerlan's webpage on travel bikes. He is a Dahon dealer and provides some details that you might find helpful.

http://www.gaerlan.com/bikes/who.html
http://www.gaerlan.com/

I would test ride as many bikes as possible. I've ridden the Bike FRiday tikit and Xootr Swift folder and both are good alternatives with their advantages. You might also find a Birdy dealer in Singapore too. Test ride the low-end model (Red?). Perhaps you want a steel travel bike ... test ride the Bike Friday 20" wheel models.

As you see, the point is test, test, test, test, and then test some more. A little bit of effort and time now will make your decision a much better one.