As we've tested neither the NR1501 or (yet) the NR1601, I can't comment on performance. There will be compromises due to the slimline format, but if that's all you've got room for, a separate receiver like the Marantz is bound to outperform your other option of a one-box home cinema solution.
Don't forget to shop around for deals on the Marantz if you do go for it - there are plenty around, and bound to be more now the 1st July price-drop has been announced