Bests & Worsts Reviews from Amazon

There's good news and bad news about this product. (Detailed review ahead.) This product is highly rated by the leading consumer testing magazine. And it's priced competitively on Amazon. I ordered 6 of these, and all arrived promptly, packed together, but in individual smaller boxes, all well cushioned. Five of the items arrived perfect, and installed easily (but more info on an important installation detail below). One of these detectors arrived with a significant manufacturer's defect. See the attached photo for a clear illustration of the defect, which made this detector uninstallable. The electrical pins inside the device were improperly positioned. This defect also interfered with the opening/closing of the battery door on the new detector. Amazon handled the exchange promptly and courteously. Now, about the installation of the OK units: There's also good news and bad news. Good news: The connecting pigtails included with the new First Alert smoke detectors are identical to the pigtails in my 10-year-old First Alert same-model detectors, which these are replacing. That means it was not necessary to un-wire and re-wire new pigtails into their wall boxes before replacing each detector. I was able simply to disconnect the old pigtail from the old detector and plug it into the new detectors. Easy! And safe! Bad news: First Alert has very SLIGHTLY modified the round plastic mounting base for the new units, compared to their own 10-year-old design. This means I had to remove the old mounting base and replace it with the new one. It's an easy step, no problem. But because the new mounting base has a smaller diameter (a "trimmer" design), the new bases expose a ring of unpainted/unwalpapered wall/ceiling surface, which requires patching. First Alert has ALSO SLIGHTLY modified the turnscrew plastic locking design of the detector, so it no longer secures completely to the 10-year-old design. This, also, means the old mounting bases cannot simply be left in place, with the new detectors simply attaching to them. In a couple of highly-visible and not-easily-patched wallpaper locations, I decided to leave the old mounting bases in place anyway (preserving the wallcovering's appearance), and discovered that the new detectors ARE able to hang fairly securely (but not perfectly) on the old bases. This is an imperfect workaround, but it DOES work, especially since the detectors are in no danger of falling off the wall (they're hardwired, electrically). Using this method will require a bit of care (a two-handed job) when changing batteries annually, to avoid pulling the detectors off their mounts. But it's not difficult. A final note: Regardless of whether these detectors are attached to their OLD mounts or to the NEW ones, the distinction is invisible from below. In fact, the wallcovering issue with the new, trimmer bases is more noticeable than the new detectors attached to the old mounts.