I have trained in silat and escrima for many years. There are a myriad of different silat systems, and most have their own version of tapi-tapi. There are also Filipino systems of silat, Indonesian systems of silat and Malaysian systems of silat (not to mention Thailand, Burma, etc.).
I like the post above of silat and kali being different methodologies teaching the same art except that it could be argued that the methodology is a part of the actual art, and is certainly how the art is transmitted. That alone guarantees the differences. I've also heard that they are "same-same" and while they have many similarities, they are not the same. I would say they are close cousins. Most FMA had influences from the Spanish and other European influences which the other Southeast Asian countries simply did not become influenced by due to the heavier Chinese influences and Dutch and English who jealously guarded the Spice Islands. Different cultures and influences with different practices and exposures to usage and outsiders creating different adaptations of the arts require evolutions of the arts that mean they are no longer the same.
Now, some parts of the southern Philippines are very similar to some parts of the Indonesian Archipelago and had fewer Spanish and Portuguese influences. They also have "kuntaw" which is a Filipino version of kun tao. So, in many instances some kali will adopt the moves of silat and vice versa, while some silat will adopt the moves of kun tao. That leads to another observation. There are some silat styles (e.g., Indonesian Mustika Kwitang), that are obviously of kun tao origin, but they acknowledge only their silat heritage, and to be honest, there has been many years of "cross pollenization," however, once you know enough to observe the differences you can see them.
There are definite subtles differences in the way the practitioners move, the methods of training, the strategies and principles employed in general between silat and kali. But there are many similarities.
I'd say pick the one that you enjoy so much that you keep showing up to train for whatever reason.