They are similar, yet different, Swiss holes like that are different than a full fab cylinder, also the shapes and water volumes are different between them, along with modularity of mouthpiece etc... And then the percs should also be different, I have not tried the inline frit barrel yet, but comparing fol to fountain frit disc (CaliBear and SamL straight fabs vs yhookah anguschen straight swiss) they are indeed similar yet noticeably different... The air flow through them and the diffusion level are different, but overall these do all fit sort of the same role, so it depends how much you like this style of piece, how much the little differences would be worth it to you, and for the price, if they would be complimentary etc...? For me, I really enjoy this style of piece, so the variants are fun to collect and rotate, although I do have my limits (sold the Gili Glass version, and will sell my OG protege, but getting the V2, plus I have vertex too, also happy with my three fabs and my other swiss piece with the right angles sooo) I will follow up and report back once I can test the prototype V2 to see how the inline frit barrel perc is to compare...