Why iRobot is the worst vacuum to own?

I don't think I am a gadget freak but systems that are "self-sustained" do attract my attention. My purchase of iRobot Roomba about four years ago was one such attraction. I had many choices then as I have now when it comes to cleaning your floors, but ease of use always tops my list for what I do and what I own. In just a couple of years I realized something got broke and after rigorous analysis I found it was the in built battery charger that was unable to charge the batteries. I found Roombas being sold in Costco and in Target and neither of these giant stores carried any accessories. What a bummer! This was the first time I was pissed. Anyhow, I looked up on the web and bought one battery and one external charger from Amazon. Amazon continues to amaze me what I can buy there but thats for sometime later. Roomba was back in business. By this time I already had three other working/partially working vacuum cleaners and out of the four I had I was very impressed by the cleaning power of that small Shark. Ease of use remained at the top of my list and I continued to roombatize my floors. I moved and after stuffing part of my basement with my stash I moved to another place and took just my Roomba with me. I could have taken Shark too but I left it there.
With in just a few months my iRobot turns it battery lights red even after the battery is just fully charged. At this time I do not know whats wrong. But still took a round to Costco and Target in hope that at least now I should get its accessories. Instead of buying a new vacuum cleaner I was still inclined to get a new battery. When I love someone my faith sticks there. Nope! Even after these many years while Target continues to keep one or two Roombas around they still do not sell any of its accessories. This time I was really pissed. I saw a good deal on a Dirt Devil and saw its bag completely full with dirt just after cleaning half of my apartment and this being just a fraction of the price I paid for Roomba four years ago. Roomba disappointed me. If you are selling something this pricey you need to make sure that its operating cost is kept to minimum. Its anybody guess why bag-less cleaners are so much popular today compared to bagged ones - it is about TCO. After paying $300 for Roomba I expected it to run for a very looong time by continuing to charge its batteries. And at least expect to get its so critical accessories to be available freely from big stores. I will continue to tell that I owned an intelligent vacuum cleaner but when it comes to cleaning your home I don't think I am going to recommend it to anyone. Its just one very bad toy to own.