I use a MacBook Air with a Magic Mouse, and needed a Bluetooth keypad. I read the negative reviews of others and ordered this product with some hesitation.
I ran into the same pairing issues as other reviewers did. I tried following the manual's instructions, which are quite confusing as others have noted, with no success.
Then I called customer service (connected with Philippines, I believe). A rep picked up quickly, and 5 min later the unit worked just fine. The problem turned out to be the batteries which were supplied with the unit -- a minor inconvenience. The rep explained that the batteries were nearly out of charge, likely because of being in a warehouse for an extended period of time. When the unit toggles between its two modes (more on the modes later in this review) without user input, it indicates that the battery needs to be changed. This point is not explained in the user manual. There is a Battery Indicator which plays a minor part during the pairing process (but apparently is not an indication of remaining battery life).
When I replaced with a new set of batteries, the unit paired easily and remained paired. The rep mentioned that fresh batteries should last 4-5 months under normal use -- about the same life as Apple's Magic Trackpad and Magic Mouse. However, this unit uses two AAA batteries, not the AA batteries used in Apple's units. Another design detail which tells you that this is not an Apple product is that the batteries are inserted side-by-side with opposite polarities (i.e., like most electric/electronic devices), not the end-to-end same polarity insertion used in Apple's products. The side-by-side arrangement also makes the battery compartment thicker than Apple's battery compartments, even though this KeyPad uses smaller AAA batteries. It would have also been more convenient to use AA batteries, so that rechargeable batteries could be shared between the Magic Trackpad and/or Magic Mouse and this Keypad.
There are two modes to the unit -- Keypad and Calculator. The Mode button in the top right toggles between the two modes, and the mode you are in currently is identified on the unit's display.
In Keypad mode, you use the unit with your computer. There is initially a jarring effect in Keypad mode which passes quickly (also not explained in the manual) -- the numbers you type are not reflected on the unit's display, but are reflected only on your computer (if paired properly). This feature makes sense, as it serves as an alert to the user that your computer is receiving input from the unit.
In Calculator mode, you use the unit like a calculator (simple arithmetic calculator). Your numeric key presses are displayed on the unit's display, and your computer is disconnected from the unit. I was able to toggle between the modes and, when returning to Keypad mode, seamlessly continued to type numbers into my computer where I had left off. The Calculator mode is indeed a convenient added touch.
Pairing with iPad 2 was also easy (first disconnect from your computer).
Construction quality -- matches the MacBook Air in color, but the material is plastic, not metallic. Adequate quality, although not up to Apple quality, as others have noted.
It is a rather large unit with big numeric keys -- I like the size, but others may not. I like the fact that you can pick up the unit and use two hands to tap out your numbers, as if using a calculator.
If you decide to purchase this unit, have a fresh pair of AAA batteries handy. If you have trouble pairing when using the batteries provided with the unit, replace the batteries and then try pairing again. If you still need to contact customer service, it was a quick and pleasant experience for me.
Rating: 3.5 stars, due to construction quality, battery type (AAA instead of AA) and battery compartment design.