Does its job well.
Inexpensive, and does exactly as advertised. Takes up little room, but the connections could be a little longer. You'll have to locate the base unit fairly close to your Wii, which may be difficult depending upon your A/V rack & furniture. Only real drawback is that you really cannot keep the rubber sleeves for the Wii remotes on the units while charging. Minor irritation, but noteworthy. If you use your Wii moderately or heavily, rechargeable batteries are a must, and this unit works well.

Does its job, but only to satisfy that requirement
While the Quad Dock does charge up to four wii-remote rechargeable battery packs at once, it does so very inconveniently. To place the remote in with the battery pack installed, the wriststrap MUST be removed. This is a bit of a pain. The best way to charge is by placing the batter pack solely into the charger; it is designed to work this way as well. HOWEVER, getting it into the right angle is difficult.

Another thing that is odd is that this charger draws power from your Wii console's AC adapter. That's right; you must plug your AC adapter into it, and then connect it to your Wii with a very short dongle. I would have preferred to have a separate 2 prong 110V AC cord.

Overall, it does work, batteries fit well into remote and 4x charging is possible, just some important oddities keep this product from really shining.

This dock rocks!
Very happy after owning the quad dock for close to 2 months now. Clever AC power adapter piggy backs on the Wii AC power cord, so you don't use a USB port or use up any outlets on your power strip. Drawing direct from AC also means faster charge times than USB models.
Another plus is the battery packs have a little extension button for the wireless connection. True, this is not a common use feature, but still shows what consideration went into product design and comes in real handy if you need to re-connect or you take your wiimote over to a different Wii. My friend has a different model charge station/battery packs that lacked this feature, and I had to put loose batteries in the wiimote and hold them in place while I pressed the connect button.
I have not tried putting my wiimote with the new battery packs into any kind of Wii accessory (e.g. wheel, gun, etc.) but to my eye the battery pack profile is exactly the same as the OEM battery covers, so my guess is these puppies will fit no problem.
Probably the coolest thing about this charging solution is that the battery packs fit securely into the charge station, even when seperated from the wiimote. This means, if you have less than 4 wiimotes, you can always have a fresh battery pack handy in case you drain one while playing.
My only complaint, and it is a small one, is the blue lights. Some may like them, but for me they are a bit too intense. I would have been happier with some small, subtle LEDs. My kids think it is pretty cool when they get up in the morning (before daylight) and all 4 charge docks are flashing cool, blue light (each recepticle has a ring of blue light that comes on when in contact with batteries and charging, and then switches to a slow flash when fully charged).
To summarize, if you are looking for a charging solution for the Wii, buy this one, even if you have only one wiimote at present. You won't regret it. For those concerned that blue lights flashing may detract from the appearance of your home (or make you think the cops are at your door), you can probably get some colored, semi-transparent tape to cover and subdue the lights.

Wii Quad Dock
I ordered this thinking that It would be a little better than the Nyko version that only charged two controllers at a time. I played for about 4 straight hours one day and the controllers were fully charged when I started. I had to stop to charge the controller I was using because it was almost dead. They said it would last 15 hours and I figured that was way more than I needed, but the 4 hours that I got out of it was a joke.

You have to remove the straps and even though I don't use them, other people like to use them and it's a pain to take the straps off and put them back on every time. The manual said it took 4 hours to charge 4 controllers (if I remember correctly), so your time to charge two would obviously take less time, but it isn't worth it because the batteries don't last long enough, especially if you are having a wii party. An hour of charge for an hour of gameplay isn't very good compared to other products out there, and that was the time I got out of the battery without the controller's sound or rumble features turned on. This is a terrible product in my opinion, and my friends thought so too. I would really recommend the Nyko charge station, but I don't want to sound like a spokesperson for their product. I also have Energizer rechargable batteries that work much better than the quad dock, so take your pick because there are many options out there that provide better results than this product.

Cool but....
i love the charging station for my 4 wii controlers i mean its awesome.But i hate how there it a sync. button on the part of the wii mote were u hold it and if u press it accendentaly it disconnects and u have to take out the battery to reconnect it. and it happens quite often its get pretty annoying. But if u can handle that this product is for u.