The Galaxy Tab 10.1 and Galaxy Tab 8.9 are similar in most respects although there are some slight differences. Obviously foremost is the difference in size between the 10.1 inch and 8.9 inch screens. Second, the weight of the Galaxy Tab 10.1 is 595 grams vs. the Galaxy Tab 8.9's 470 grams. The next difference is the battery. The Galaxy Tab 10.1 has a 6800 mAH battery while the Galaxy Tab 8.9 has a 6000 mAH battery. One unconfirmed difference between the two is that the Galaxy Tab 8.9 is reported to have a built-in HDMI port while the Galaxy Tab 10.1 has only the standard port connector so you'll have to carry an extra accessory for HDMI output on the 10.1 Finally, there's price. While not a big difference the Galaxy Tab 10.1 is expected to cost $499 while the Galaxy Tab 8.9 is expected to be $469.