Thinking about getting one of this gadget. However, I notice that there are three types for Roomba : Standard, Roomba Red (or is thisPro Lite?), and Roomba Discovery (or the one with SE on it). The price starts around US $150, $225 form Pro-lite and $260 for Discovery. What are the differences in those three? Which one is the best one... the most expensive one (the Discovery)? I like the red colour (Pro lite)... but does it has less features than the Discovery? Then, I saw the Electrolux Trilobite ... a very nice machine, but it costs around US $1600! Why is there so much difference in cost between Roomba and Trilobite? Is Trilobite for real, heavy duty cleaning (rather than a robotic "toy" like Roomba)? Is it worth to get $1600 vacum cleaner in the long run? Has it better quality, service and performance? Need some opinion on this. Thanks. Do any of these cleaners need a special order vacuum bags, which is only supplied by the manufacturer? I also heard about rechargable batteries... How fast that we need to keep buying new batteries? I am a little wary that I can get sucked by these manufacturers, which probably have strategy to sell more of the accessories (just like a cheap printers, when you have to pay a fortune for the ink... or a free cell phone, but you have to pay arm and legs to use it). Thanks for info.