Well, i have had a 10.1 since early in the release, and ran into only a few of these issues before i updated to the 3.2 firmware. I have had some issues with the browser as well.
When you talk about the back button not working without multiple presses, i have the same issue on some websites. I have tracked it down to a possibility that it is caused by a flash based ad on the page. These ads tend to update the whole page sometimes, so when you press the back button, it has to be done numerous times to get the page to actually return.
With the browser not loading or hanging, this is going to be a given when they are trying to use a mobile browser on a tablet. These browsers on the market all have the same issue, they are more of a lite version, instead of a full on desktop version.
This is due to memory issues and such, so it is really hard blame the hardware, as it is quite capable to run any software as needed, it is just the Honeycomb OS. A bastard operating system that is more mobile instead of tablet. Ice Cream Sandwich is supposed to solve a lot of issues, but will Samsung give us an update for the Tab 10.1 or not?