the flash port to ios4 is **** it cant even do youtube it does ads though if you like them.
to be fair it is being called a beta so best to wait for future.
if nokia are scared of peformance issues with flash 10.1 on the N900 then why not just release a downloadable beta like on android so ppl have the option to upgrade and test, just leave it out of firmware so its not forced on people.