For me the biggy has been lack of multitasking. It's so annoying to open a link in a new tab, only to come back and have safari reload the entire page I was just on. It's like the iPad's browser has Alzheimer's.
I wouldn't get too excited. With only 256MB of RAM, it's still going to happen on the iPad :/
Having just tested it, I'm happy to report you're wrong.
Wait until you have more apps running..
Nope. No issues. I'm betting safari gets priority.
Apps in the background may have their resources reclaimed, or be shut down, if foreground apps need the RAM.
Also consider that many apps are using the same (system) libraries, which are only loaded once.