I would suggest that people do not trust-by-default anything they read on the web, especially when written by people (or AI) whose main motive is selling you something and especially when they somehow come out the best in comparisons.
One kinda-obvious fact, even with quickest look at their graphs: SPN routes traffic around its own nodes only. So, at best (and little longer glance seems to indicate the situation is far from best), it can only be as “safe” as Tor which by some disaster and decades long work had 100% of its nodes compromised (e.g. run by NSA or whoever).
As the main point of Tor is exactly that nodes are run by different people in different jurisdictions with different risks, and that not one of them knows what other has done, so when one or dozen entities are compromised it is still mostly (and often totally) fine.
Sure, e.g. Trump might given authority to NSA and control all US nodes, but it is unlikely that he himself at the same time also controls all Russian nodes, and all Ukrainian nodes, and all Iran nodes, all German nodes, all UAE nodes, and all Hungarian nodes, etc.
With SPN, Safing Gmbh (kinda obviously) controls all the SPN nodes. Thus all of the nodes know (or can know if they care) what all the others are doing (as they’re all owned by same company, so single request of relevant government, or single bribed employee with high enough access can see and change everything everyone is doing [unless you add your own extra steps of security on top of SPN)). You basically put all your eggs in one basket, creating a SPOF.
That is, like, enormous difference (bigger than e.g. using VPN vs. using plain HTTPS).
(Note: this is true not only about SPN, but about all entities which control all points in communication. If they’re forced to log/disclose information, you are actually worse then if you were not using any VPN/SPN whatsoever).
But, as others have said, it all depends on what you are dealing with. If you only want to avoid seeing targeted Viagra ads or want to see geofenced Youtube content, it is obviously enormously different situation than if you’re person of interest in totalitarian regime and your (and your family) heads are literally on the chopping block if you’re found doing the wrong thing.