Against the magnetic attachment is in principle nothing to say, but you should look at the back of the alarm before buying. I have smoke detectors from VisorTech, have their support towards the ceiling a circular recess of 6 cm diameter (see photo), ie it remains virtually no adhesive surface for the Magnetolink who has an estimated diameter of 7 cm. (I have glued as a last resort with laying tape a 1 mm thick large diameter washer into the recess of the smoke detector in order to obtain sufficient adhesive surface).
Tip: contrary to the instructions I have to part with the magnets glued to the ceiling. If a smoke alarm be replaced in the future, then I just need any metal part on the back for sticking instead to buy a complete new Magnetolink set. Experience has shown that does not fit the new smoke detector namely mostly in the old bracket.