I bought this about three weeks ago and it is the best thing I have ever done for my dental health. I find it so easy to use and my mouth and teeth are already healthier. I had blisters on my gums and they are now gone, since using this twice a day.
Got this to replace an obsolete model I'd had for 20-plus years. The new one seems a bit flimsier than the old one; its reservoir holds 40% less water; it doesn't (the old one did) come with a wall mount. None of these are fatal flaws, but I doubt whether this unit will last anywhere are long as the old one; check back in, say, 10 years!
This is my fifth unit over the years. Worst design ever. Top is problem. It has to be removed completely and put back on with precision or it will fall in reservoir. Also had to run vinegar through it for almost two weeks to remove unpleasant taste. On a good note, works as well as all others I have owned.