As far as I think there is not much difference in Report Studio.Its much easier than v7.3.Also there are some additional features in 8 which is not that difficult to handle.

The additional features are

u can create one more type of report like map report in addition to list, crosstab ,chart and repeater

Also there is another prompt called tree prompt which organizes data hierarchically.

Rest all is same , there is some change in master detail query too.