OK, for most the OE suspension is fine. Commuting, riding around town, etc... For others, where the rider is a bigger guy, like me, or there is an expectation of higher suspension performance, like me, based on decades of riding with high performance suspension, like me too, this upgrade is worthwhile.
Would I have been happier with the SP, adding a lot of the Strada stuff to permit the 300 to 400 mile days of exploration? I just don't like the idea of lifting a leg over that nose bleed seat height all day, nor not being flat foot.
The best compromise is what I did. A regular ride height Strada and this suspension upgrade.
Considering that the new 939 has the same chassis and suspension, this review provides 3rd party insight as to the difference between OE and SP suspension.
In addition, I ride a lot off-road on easy Jeep trails and just barely paved fire roads in National Forests. For these roads the OE suspension just plain doesn't work at the speeds I ride.
These backroad passes allow for spirited riding without traffic or upsetting law enforcement.