I'm not averse to the Xoom.. the Transformer and Galaxy Tab's caught my eye... also thought I read somewhere that Motorola is working on a new Xoom tablet or fixing the current one or something like that...
The Galaxay tab is by far the prettiest of the bunch. I think it looks better than the iPad. It's nice and light and thin and pretty. However, it has no microSD port or any storage expansion unless you get the 3G/4G version. For me, that was a deal breaker. I could do with needing the dongle for USB, but no storage expansion causes problems when you use it for PDFs and other documents. The "fixing" the Xoom may be the microSD support that Motorola says they were waiting on Google to release. As of early June it is supposed to be fixed, with the release of Android 3.2. The other thing to consider is that 3.2 will be the last Honeycomb release. Going forward it will be Ice Cream Sandwich. It also could be the Xoom 2 rumor.
Everyone has their personal preferences about styling and features. Go to your local big box store and play with the tablets. Get a feel for them and decide which you like. Decide up front whether you need expandable storage, before you hold the Samsung.