We are veterans of WDW/Universal Studios touring because we do that once annually during the holidays. I would suggest the split stay as others have alluded. I don't know what your entire vacation budget is as far as days go, but you'll want 3 or 4 days at WDW and 2 or 3 days at UO. When staying at a UO resort, you get "front of the line" access to the rides which is worth gold.
Therefore the following would be the best a split stay with the following:
1) WDW your hotel of choice.
2) US - your hotel of choice: Hard Rock is our favorite: Closest walk to the parks. Our kids love the theming. Coolest pool. If you are visiting during the winter, they REALLY keep the water nice and warm during that time. Nice rooms, good service. The other hotels are good choices as well - RPR a little cheaper but longer walk. Portofino, differrent atmosphere, longer walk as well (but with boat shuttles).
Either way, do your research, split your stay. You'll enjoy BOTH WDW and UO much more with access to each park.