Dampening wise while they do make your bike a "magic carpet" compared to OEM shocks I'd still stay away from Öhlins when it comes to heavy loads, long distance over bad roads combination. WP is also questionable in this sense. Wilbers is probably the worst quality among the bunch.
Most of aftermarket shocks just aren't designed for long distance abuse under heavy loaded overland bike. They're designed for light bike, short burst/frequent service conditions. Hence they're called "Racing" products.
In many cases OEM shocks work optimal if you put strong progressive spring to avoid bottoming out and let it do less work (less main seal friction and no overheating). Although heavy, not so finely-tuned dampening and mostly "unservicable" (a good suspension specialist can overhaul ANY "unservicable" shock no problem) the stock shocks have one good advantage - they mostly have strong steel bodies that can take abuse under heavy bike without deforming on long term. There're many exceptions of course, depending on the model and manufacturer.
Our lightweight "racing" aluminium body Öhlins split in half in Pakistan. Wilbers just blow the main seals every 1000km or so. I think we spent some 1/10 of all RTW budget on repairing Öhlins and Wilbers in third-world conditions.
The only aftermarket shock that worked for us was Hyperpro - we just couldn't kill them while the bike around it was desintegrating. Although Hyperpros are also sold under "racing" guise but in comparison with Öhlins/WP/Wilbers shocks Hyperpros look more like a heavy duty shocks and probably heavier too. The working rod is considerably thicker compared to both Öhlins and Wilbers, and the main body is more robustly built. There's no fancy gold or white colours or other shiny "bling" details on it, so they're probably not for those who like fancy looking shocks, but function wise they rank very high in terms of reliability after our RTW, way ahead to the famous Öhlins from our example. As said it was the only shock that worked flawlessly.
We didn't service our Hyperpro for some 40 000km of African abuse, all the bike-side bushes were worn out and even connections/frame bent, couldn't believe they still worked after all the horror we had with Öhlins and Wilbers that we serviced more frequently, while all the bushes were OK, everything straight and the road conditions were much nicer for them.
Cost wise we could buy a full Hypepro "3D" shock with separate reservoir cheaper compared to Öhlins simpler emulsion (singly body) shock. Only Wilbers was in the similar price range, but horrible reliability, not even worth looking for more serious overland travellers, unless they've dramatically improved their shock design in recent years.
For longer distances without frequent service I'd say aim for remote/separate-reservoir (or "piggyback") shocks for better cooling (overheated emulsion-shock was a problem for us!) and arguably better reliability - they have gas and oil separated through a rubber collapsing bladder inside the reservoir that understands no friction, it's probably more easy for the main seals too.
It's all IMHO of course and from our personal experiences and lessons learned on our RTW. Everybody should make their own conclusions and choices since travelling is an individual experience.