So-net looks like an alright service, monthly fee looks about average too. It's up to you, but if you're a bit tight, I would suggest getting Hong Kong Broadband instead. It provides a 10Mb (megabit) service, and for something like HK$90 something a month.
Yes, it might sound like it's too good to be true, however it doesn't seem to be the case. I've tested the speed several times in the past just to confirm whether I really did have a 10M connection, and sure enough, when I saw that I was getting 1.0MBps - 1.1MBps (megabytes per second - close to 9M), I knew I did.
There's only one small catch though, when connecting to the network, one is required to open up this small & annoying IE connection window. It can be taken away using the right software however, or you could also just reboot while connected, leaving you connected but without the window.
I've also tried iCable in a neighbours system, but I didn't like it because the speeds fluctuate too much sometimes.