You may want to consider the new iRobot Roomba 700 Series, which is already available in US market. The iRobot Roomba 700 Series is using the new technology (optical and acoustic sensors) to find dirt and debris and it also using HEPA filter instead of standard filter now. I personally like the model Roomba 770. Below is the comparison between 700 and 500 series:-

The primary advancements of the iRobot Roomba 700 Series are in its cleaning system. Maintaining a clean home is very important to our customers, so we constantly focus on improving the robot’s vacuuming abilities. The 700 Series Advanced Cleaning System provides cleaning improvements over the 500 Series in several ways:

- The Advanced Cleaning Head picks up more dirt than earlier designs and specifically works better with fine dust.
- AeroVac™ Series 2 Bin incorporates dual HEPA filters to help Roomba pick up and capture dust particles as small as 0.3 microns.
- The upgraded cleaning head and AeroVac Series 2 Bin combine to better handle hair by efficiently moving it to the dust bin and better resisting buildup on the brush bearings.
- Dirt Detect™ Series 2 Technology (770 and 780 models only) allows Roomba to spend more time cleaning a wider variety of concentrated debris. In addition to Dirt Detect Series 1 Technology, which uses an acoustic sensor to find dirtier areas (typically hard, small particles like sand), Dirt Detect Series 2 incorporates an optical sensor to “see” dirtier areas and spend more time cleaning them (think paper chads, popcorn and other larger, softer particles).
- Roomba now employs our Persistent Pass Cleaning Method when it senses excessive dirt and debris, using a back and forth cleaning motion to apply extra elbow grease where it’s needed most.

At the moment, this new series is only selling and ship to in US and Canada. But If you have someone going to US then you can get them to deliver to the US address (Hotel address) and then bring it back to Malaysia. The new series price is still cheaper than the old 500 series model Well, I will be getting my wife to bring back one unit next month from US.

For more details and products comparison, check this out at http://bit.ly/irobotroomba700