I also had a Galaxy tab also which I liked but would agree that Android for phones doesn't work as well for tablets. I think a fair comparison would have to be between a Honeycomb tablet and the HP TP. Unfortunately I do not have any time on a Honeycomb tablet (was in the market for one when the HP TP deal came up).
The hardware on the Touch is solid, as I said the screen is beautiful and can be seen from all different angles, it's as good as the iPad 2's. The body is sleek (actually to be honest reminds me a lot of my iPhone 3G) and feels really nice in your hand. It is not as thin as an iPad 2 (which I have some time on since my father owns one) but the size doesn't bother me at all, like I said it is very sleek.
I wanted a tablet for internet, ereader, and causal gaming. The internet experience get's my full approval. In the three day's that I have owned it (including sunday with the hurricane) it hasn't dissappointed me yet, it's fast and very fluid. I haven't tried it as an ereader since I really don't want to buy into kindle yet, I am hoping for something better to come out. Same goes for gaming, just haven't gotten the time to look into it yet. The battery has held up to major internet abuse, I put it on the charger yesterday after running it all day with 68% left on it.
For the original asking price of $500+ I would have spent the money on a Honeycomb Tablet, I just didn't have an interest in webOS. But after using it I can now say that it would have been worth the price, it's a solid unit and webOS is a nice OS. You will wish that some of the stuff in webOS was in Android. The big question on everyones mind is what is the future of developer support. If HP didn't kill this thing off, the lack of apps would have, I really hope developers support it since there are millions of them out there now.
For $149 there is nothing else out there like it, you will not find a better experience for the money. Even if all I could do was surf the internet on this thing it would be worth that price. Some of my opinions may change as I try to do other things with it but my base opinion won't change, it's worth that price by far (I know this sounds confusing).