Both claim to be the sole path to God (or did at some point )
Both claim to reach back to first century christians ,( though JW`s are a bit ambiguous about this)
The R.C Church has a Pope , the J.W.`s have a governing body ,both providing spiritual food to the faithful
Both accept the name" Jehovah" as the personal name of God , with the R.C.church also accepting the much widely accepted name of" Yahweh" a more correct pronunciation
The R.C. church first giving that name" Jehovah" by Raymundus Martinus in about the thirteenth century. That name was derived from the four letters of the tetragrammaton translated in english as YHWH or JHVH and the catholic monk inserting the vowel letters to either read JeHoVaH or YaWeH
The Roman Catholic church holds sacrement the confessional ,whats divulged to a preist in the confessional is between only the preist and God,nobody else.
The Jehovah`s Witnesses say that what is divulged in a judicial enquiry (confessional ) is the same as the R.C .confessional , privelegded information, penitent priveledge. However the difference here is the WTB&TS eg: Jehovah`s Witnesses pass on that information to the Governing Body , the members that make up that body.So it is not just between the three elders on a judicial committee and God it now becomes common knowledge to a much wider audience , the governing body .
Of course their are doctrinal differences between the R.C.Church and Jehovah`s Witnesses as their are with the thousands of faiths claiming to be christian ,however the JW`s in their 130+ years of existence have never demonized any other religion like they have with the Roman Catholic Church , and yet they are so similar.
I would welcome any other similarities you can come up with / or correct me where I am wrong