I have owned a Sprint Tab since January and have never looked back.
I thought about holding out for a Xoom but knew in messing with my mother's iPad that 10", regardless of aspect ratio is just too big for me. The Tab is a great size; its big enough to make a great ebook reader, web browser and movie player while being small enough that I can throw it in my back pocket if I need to quickly free up a hand. Its perfectly capable of playing every game I can throw at it. And although its not using Honeycomb, I dont have any problems with Froyo on it.
I have seen a few apps not scale to the bigger screen, such as Mint.com's app, but its extremely rare and the same apps have the problem on my father's Xoom.
Sure, the dual core xoom may be technically better than the tab but I find functionality more important than raw power in a tablet. If I want raw power, I will use my desktop computer. My tablet fits my life style perfectly and I never leave home without it, anywhere. There is a host of applications I use every single day that greatly benefit from the 7" screen. And the nice thing is I can hold the device in one or two hands and not feel that its awkward at all, unlike the Xoom or iPad.
Ultimately, I think it comes down to what you want to do on your tablet and where you'll be doing it at. I love gaming (SNES Emulator and Pocket Legends particularly), browsing the web and reading ebooks pretty much anywhere I want. For those things, I would hate to have to use a bigger device due to awkward ways one would hold it. But if you are looking for a full notebook replacement, like my father is, the xoom is slightly better (though I dont think any tablet is to that point yet).
My wife loved my tab so much, she wanted one but instead went with the Nook Color, which I recently put Honeycomb on for her. She loves that and we both use them every day. I would have gotten her the Tab Wifi but we got her nook before I was aware the wifi Tab was coming out.
Every time someone asks for my opinion on the tablet to buy, I say look at the Galaxy Tab first and last. Its a great device for a good price (the wifi only one anyway) that is nearly as capable as any other tablet out there. I for one have no regrets about mine.
I just typed this whole thing on my Tab without having to put it down to type or lift my hands off the device; lets see a Xoon or iPad do that.