After reading a few poor reviews of this product, I was slightly hesitant before buying it. However, I went along with the purchase anyway. An action which turned out to be a huge mistake.
The product arrived in the expected time period, but that's where compliments end. At the time of ordering, the description of the product offered a free mains charger with your purchase - which didn't arrive. The battery packs provided to put into your Wii remotes barely fit. The docking station very rarely charged the remotes at all; and when they did, the battery life was never more than an hour (after charging for around 12 hours!).
Totally unimpressed with this product and am currently awaiting a refund. Hopefully their customer service won't be as disappointing as the product.
Edit (10/03/10): Having requested a refund, I was sent a replacement charger instead. Hoping that this might do the job you expect, I went ahead and tried it anyway. The docking station had no problem recognising the remotes and seemingly charging them; however, after around six hours of charging, I got approximately two minutes usage from the batteries. Currently awaiting a refund - hopefully they'll get it right this time.
Terrible product, terrible customer service - avoid at all costs!