That's a tough question to answer. Seadrill Partners has significantly less number of rigs to operate than Seadrill; meaning SDLP has higher business risk volatility, to the upside and downside, than SDRL. Also, Seadrill Partners has a critical debt issue coming due in 1Q2021 that must be rolled over, and thus they need to quickly increase its future revenue visibility as it has almost no backlog into 2021 and beyond.
Limiting my response to your parameter of SDRL v. SDLP ... so I'm ignoring RIG, NE, VAL, etc ...
Realistically the key issue is are there several multi-year UDW development drilling contracts to be announced soon? And where would they be. If Canada, then SDLP has the edge over SDRL. If GOM, the edge also goes to SDLP. If Brasil, the edge goes to SDRL. If Angola, the initial edge goes to SDRL, but subsequent deals may benefit SDLP instead. But if an announced multi-year term contract first happens in the Eastern Hemisphere, where management seems to be focused, then perhaps both companies have upside potential ... and there I would lean towards SDLP with its twin West Polaris and West Capella positioned in that area, especially if the work is offshore East Africa's Mozambique.
One wild card are the 5 newbuilds owned by the company you didn't mention, Oslo stock exchange traded Northern Drilling (NODL). Before the end of this week there should be a press release by SDRL announcing the terms of a bare-boat charter of newbuild HE-SS West Mira from NODL, which is scheduled to start its first drilling contract ~ this coming Friday in the North Sea for 10 wells firm (30 months) + options at ~ $300+k/d. Likely similar bare-boat terms would involve SDRL and NODL for the West Bollsta which has a similar contract with essentially the same E&P JV partners as West Mira. The other three NODL newbuilds, all drillships in South Korea's DSME shipyard, are perhaps out a year and perhaps could be bare-boat chartered by SDLP instead of SDRL.
In terms of new contracts, the increase in direct negotiations, as opposed to tenders, increases the chance of a market surprise. Especially since the direct negotiations seem to surround both (a) the most desirable Tier 1 harsh-environment and benign environment UDW rigs and (b) Gen 6 drillships that have excellent operating history and meet the equipment/configuration required by the customer.
One place running under the radar these days seems to be the offshore drilling for the LNG mega-projects in Mozambique. Whether Eni may take a related-party Saipem drilling rig for only its own wildcatting and Coral LNG operations, or also take a Saipem rig for its Eni/Exxon Area 4 $30Bn LNG mega-project remains to be announced. Similar large multi-year drilling opportunity exists for the Anadarko-to-OccidentalPetroleum-to-Total Area 1 $25Bn LNG project.
I will pretend SDRL's up to 5 J-Up rigs, roughly 15 years of contracts for Qatar, via Qatar's wholly -owned subsidiary Gulf Drilling, are already factored in to the current PPS.
Bottom line to your question ... , and all this is IMO, it depends on what/where long-term work gets announced first, and who gets selected to do the offshore drilling. T.D.