840 mount is not as snug as my old 530

All Edge models undergo extensive testing to confirm they perform as expected in our mounts.  We acknowledge and expect some slight differences in the customer experience of different Edge products.  Edge 840 meets all of the same performance criteria as our other Edge units

I'm sorry, but I would definitely beg to differ on this. I've tested the Edge 840 with both original Garmin out-front mounts and high-quality aftermarket alloy mounts (e.g. K-Edge). While the Edge 840 snaps into the place when mounted, it has significant visible play in all these mounts. It basically rattles. By comparison, all the Garmin units I've had over the years (Edge 810. 820, and 830) are 100% rock solid. The difference with the 840 is absolutely visible and is much more than what you call "some slight differences in the customer experience."  Frankly, I really don't understand how this design passed the "extensive testing" process you refer to. I'm not talking about "performance criteria", but a structural design aspect (the mounting tabs). It simply feels as if the mounting tabs were somehow undersized, either in thickness/height or width. The best course of action would be to redesign the tabs, since they are replaceable in any case.

Oh, btw, I've also tested the Edge 1040 and that mounts just as solidly as the older models, so the exception seems to be the 840/540

Does that mean if the tabs on an 840 are thinner than the 830 and it rattles in the mount the unit is defective and you will replace it? 

But the replacement will just rattle the same (I've tried a few in store). It would be fantastic if they could manufacture a thicker/wider mount kit for it. It's just a piece of plastic, after all

Pretty weak response from Garmin.  Obviously a lot of people are reporting this issue.  It would be wise to look into it more vs writing some blanket statement about extensive testing.

I fully agree. However, I've just tested another 840 unit today in store and I was pleasantly surprised that it had no play (tried with 2 Garmin out front mounts, an old one and a new one). It didn't snap into place on the mount as strongly as the 830, but at least it did not wiggle at all once in place.

I'm actually wondering if some mounting tab batches are undersized (defective) or possibly the 2 tiny fixing screws on the back are not fully tightened?

Have to disagree. My 1040 visibly ‘wobbles’ in both the supplied Garmin mount and also 2 separate K-Edge mounts. I have to put about 4 or 5 small squares of electrical tape into the mounts to stop this happening. 

Interesting, the 1040 I tried in store felt rock solid (esp. compared with the 840 units that had some play in the mounts). But then this definitely sounds like variation in manufacturing tolerances. :(

I just got a new 840. The mount is rock solid so far.