Off-topic but this MA900 thread isn't exactly sizzling with activity, so I think your interest is worth a reply. I'm no pro-headphone-aphile though - I'm a thoroughly mid-fi dude. But I'll tell you what I think. First, as I said above, I jumped on the Z1R / WM1A combo because I was able to make out like a bandit on the purchase. In the US where Sony has their authorized dealers by the balls and full retail pricing prevails on their upscale stuff, those two items would be $3500. My ceiling for what it was worth to me to upgrade my gear was really more like $2k max, but I stretched it to $2300 because hey, what a deal.
I can't compare the Z1R to the Focal Clear for you, nor would I think it a proper comparison. The Z1R is a closed headphone. In reviews you will see it said that the Z1R sounds like an open headphone. Ehhh, yes and no. If you know anything about the Z1R, then you know the earcup is a stainless steel mesh over a special thick paper in a parabolic shape (traditional Japanese washi-style, Candian softwoods, yada yada.) Thing is, it really works. It practically eliminates interior resonance, and does a decent job at isolating too. At reasonable listening volumes, my wife and daughter both say they can't hear a thing from me now. And I am in my own little world, isolated from them. It's not enough to block out TV being watched in the same room, but I have IEM's that can't do that either. But anyway, I guess it's because that paper liner is air-permeable even if its not sound permeable, but what the Z1R doesn't do is put a lot of pressure on the ear canal like almost any other closed headphone I've tried. Treble detail is there, but no icepick. Bass thump is there, but no feeling of a physical assault on your eardrum. Drastically reduced fatigue over long listening sessions. This, in my experience, is one of the major "pros" of an open headphone vs. closed. But the Z1R has this "pro." It's the best closed-headphone you're gonna find, but I wouldn't be surprised if the Focal Clear sounds a little better. It's easier to make an open headphone sound good, period. But my wife and daughter are in the kitchen making something right now. I'm listening to some J.J. Cale and I can't hear them, and they can't hear me. That's the justification for the cost differential of Clear vs. Z1R.
I can compare the Z1R to the MA900. It was actually rather shocking to me, a little while ago I tried them both out on my WM1A, the MA900 on the single-ended jack and the Z1R on balanced. On comfort, the MA900 trounces the Z1R and everything else (I haven't tried the F1). You know this already. It weighs nothing and feels like nothing on your head. The Z1R is extremely comfortable though - thick padding, soft leather, very luxurious. But it's there, on your head, you know it. You might forget you're even wearing the MA900, but with the Z1R you will know its there, but be impressed by how comfortable it is. It is also exceptionally well-built. Metal and leather. Precise clicks. Memory foam. No cable microphonics unless you purposely induce it. And for sound -- this is why I was shocked. I plugged the MA900 in my WM1A when I first got it a few weeks ago, just to function-check the DAP. But today I really listened to it, and the Z1R has spoiled me, badly. The MA900 now sounds very restricted in bass and treble extension, lacking detail, muddy bass, and lacking sparkle. I didn't find anything lacking with the MA900's sound before the Z1R. For the money, obviously the Z1R should sound a lot better, but I didn't expect it to take the shine off my MA900 so drastically. Example: Steely Dan, Rikki Don't Lose That Number, marimba intro. With the MA900 I can hear every note, but it's 'slurred' just the slightest bit during the fast run. With the Z1R, I not only hear each note distinctly from the next, I can hear the mallet smacks. Impressive. I catch extra detail and more space to instruments than I've heard before on familiar music with these headphones all the time.
Again, I can't help you with Z1R vs. Clear. If I had a home environment where an open headphone was appropriate more frequently, I might have gotten something different. But I'm very happy with the Z1R, and since my wife doesn't have to hear my music anymore she likes it too.