I wore Phileas today. Here are my impressions after one wearing.
There is a very strong, almost uncanny resemblance to Yatagan. But I completely agree with Stranger. Phileas is softer, rounder, much smoother, richer, more refined overall.
I like Yatagan, but it's so wild smelling that I generally reserve it for use when I'm outside in the yard or going for a walk. I dare not wear it to the office or to social gatherings. But I don't feel so self-conscious about Phileas. I wore it to the office today, and while I was a bit concerned at first, I quickly adapted to the way it smelled on me and forgot about the effect it might be having on my colleagues. Phileas is more restrained and elegant than Yatagan. It's not as outdoorsy or rough in feel as Yatagan. It's Randolph Scott compared to Yatagan's John Wayne, more restrained, serious, and less boisterious, but still very masculine.
The so-called celery note is definitely there. I think this is an accord of various herbal notes, which to me smells like a combination of basil and thyme, and perhaps sage and juniper. But it is extremely well integrated in Phileas, much more so than in Yatagan. That note can be shouty in Yatagan, but it's more modulated in Phileas. Phileas, like the other Nina Ricci frags I've worn, is exceptionally well put together. Like it or not, it's an impressive fragrance.
There's a soft, subtle, leathery note underlying the herbal accord in Phileas which makes it rounder and fuller than Yatagan. Although it is an extremely dry fragrance it does seem to me a little sweeter than Yatagan.
I much prefer Phileas over Yatagan, based on my limited experience with both. It's a tough call for you. I'd say that if you don't like Yatagan you probably won't like Phileas. But keep in mind that the extra softness, smoothness, richness, and complexity of Phileas makes it easier to like and more wearable than Yatagan. I cannot say if that will be enough for you. For me it's a definite winner. In fact I've just made arrangements to get another bottle
Also, as others have pointed out, it is difficult to find now, and therefore collectable. You might want it for its rarity. But if you do buy it and hate it, you can most likely easily sell it.