Hi,
I just bought a scooba and a roomba from iRobot in US. The one in Singapore is selling abt $1300 and I got both from US at abt $800 plus shipping and delivery. Of course the voltage and everything is different and I made some minor modifications to the circuitry and now it works fine. =)
I love the roomba, cleans without much hassle. Just charge it and let it go. It doesn't even have a bag to contain the rubbish so just open up the back of the roomba and throw the dirt away. Easy as that.
As for the scooba, the problem with it is that it needs to use the clorox solution that iRobot sells. I tried to put vineger which is suggested by some sites but it smells really strong. My solution for laminate flooring works with it so I could use that but as for my kitchen tiles, I still can't find something that it accepts. Just have to try and error.
Let me know if you have any questions on both the scooba and roomba. Overall, I think it's definitely worth to buy it than to hire a maid.