Pros: This battery works as promised: It will extend the battery life of your little Eee-pc by a factor 2. Simply click it in and it can be used straight away. As mentioned in the other reviews it does indeed make the Eee a little more high, but that is not really a disadvantage.

Cons: Originally I ordered this battery for a friend of mine who has a 900HD, but surprisingly the 900HD uses a different connector then the 900. Hopefully Dealextreme will come up with a simular battery for that model as well, because this one cannot be used. Now I am using it with my 900, which works flawlessly. Make sure you check the battery number of your original battery with the ones mentioned above and you should be fine.
Two other major disadvantages are the weight and the size, but these are to be expected for an extended battery.

Other Thoughts: Check your battery number and order!

Bottomline: A great battery at a great price. Just make sure you check the battery number carefully before ordering. With all the different model numbers out there it can become a little confusing.