APOLOGIES! MISTOOK WITH ANOTHER COMPANY!There are many, many brands. ResMed is just one of many; take a quick look here for some good value models, or a site like this will easily overwhelm you with options.
However, I think your fear of the models being discontinued is unfounded.
I am using a Resmed S9, and it's almost 3 years old now. No issues thus far, and I only have to change a new filter regularly (aside from the usual like masks and tubes)
The latest and greatest is the S10 series, which I believe was released in Q3 last year. Both the S8 (2 generations ago) and S7 (3 generations ago) are still popular units that you can get parts for, and I'm sure if you have issues your provider should be able to help you to service it if you had one. They are rather popular units, and you can still pick up a new S8 AutoSet II new today (~USD380), which is pretty good value too - price is not the only good reason to pick up an older model, the S8 is one of the more compact units, and often recommended for those who need to travel often.
The clinic that you did your sleep study at, has a list of CPAP retailers in Singapore. There are quite a number of them, each carrying different brands. Ask your doctor for the list, call them up and ask about their prices, and get a general feel of their support. However, I would also recommend asking on forums like cpaptalk.com to decide what would be a good first unit. (I also recommend buying one online instead; they're significantly cheaper than buying locally...)
While you shouldn't expect a CPAP machine to continue working for the rest of your life, you don't always need the latest and greatest (although it does seem it could be nice to have), and I would think you can expect quite a few years of service from your machine.
actually its for my dad. he was using resmed but somehow the agent got changed along the way and now he got an agent that is working with another company. not convenient to say out their company but the service really sucks.
from the reviews here, maybe i will ask him to try resmed back. how about those websites like CPAP.COM.SG - Singapore CPAP Machines and Masks for OSA Therapy