Leather Oud is a pretty unique and captivating fragrance. I don't find Oud Ispahan as interesting - on my skin, it is little rose and mostly smoky oud chips (like in Leather Oud) plus patchouli.
For a rose oud combo, I find OI very dry, dark and smoky. Personally, I much prefer other rose oud scents such as New York Oud, Kilian Rose Oud, and Tom Ford Noir de Noir. For something with a similar feel (dry, smoky complex rose), I much prefer Portrait of a Lady.