What is the best sounding Mahler symphony cycle?

@mayoradamwest , @schubert 
The Fisher/Mahler are certainly audiophile quality recordings, and maybe that's one of the reasons for my enthusiastic response to them. I do think Fisher has a good grasp of Mahler from what I've heard. But since there's no compilation of the cycle, I'm exploring the symphonies one at a time.
It's a joy hearing symphonic music recorded with great care using proper microphone placement.

I think it's Grammaphone who lists the Budapest as a world class orchestra, currently rated at number 9.

To add to other's comments, I agree that Haitink/Chicago is top-class Mahler.

I think we are spoiled for choice in Mahler.  The greatest Orchestras —in no particular order, the Berliner Philharmoniker (the fashionable way  to refer to that ensemble), Vienna Philharmonic, Bavarian Radio Symphony, Amsterdam Concertgebouw, Chicago Symphony)—have all recorded multiple Mahler cycles. The Cleveland, London Symphony, Philharmonia have all had significant Mahler recorded histories.  The New York Philharmonic cycles with Bernstein (I am more familiar with the sixties cycle) and the London Philharmonic live recordings with Tennstedt represent two cycles with excellent ensembles /Conductor combos with particular Mahler affinities. 
  As I alluded to in my first post, lately there has been an explosion of Mahler recordings, many with Orchestras that perhaps aren’t thought of conventionally as ready for prime time.  Witness Fisher brother #2 and his hardworking Dusseldorfers.  I haven’t heard many of these although the reviews are excellent.

Regarding Haitink/CSO, I live in Chicago and was present at some of the concerts from which the aforementioned recordings were made.  My favorite Haitink/CSO Mahler concert was the First, and for some reason I never acquired the recording that was issued, because I don’t think it could match the experience of that night.
  I was a bit disappointed with the recording of the Third, which as I foreshadowed above, dulled the memory of a fine evening in the Hall.  To me the sound of the recording is a bit dry in places, and not consistent with my aural memory of the evening.  Curiously I don’t feel that way about the Haitink/CSO Sixth, but otoh the Sixth doesn’t really play to Haitink’s strengths (his Amsterdam recording is relatively blah, but his Amsterdam cycle on BluRay is a sonic treat).

Regarding Fisher and Budapest, I heard them in concert here this year on tour.  Their Channel Classics recordings strike me as being faithful at capturing their sonority.  They have a lean, finely chiseled sound.  Their woodwinds have great character.  The brass is finely tuned.  The CSO   brass would undoubtedly blow them halfway to Milwaukee if they had a shootout, but the Budapesters aren’t trying to win a testosterone war.  The Orchestra that they remind me the most of is the Czech Philharmonic, but the Budapest has a bit more heft in the strings.

@mahler123 that’s just the point with Budapest. They are a fine orchestra but really not at the same level as an orchestra like Chicago. While interpretation is a part, at some point it’s closer to a professional sport and some teams just have more talented players. Perhaps I am showing my hand, but as a player in professional orchestras, I find Budapest’s playing quite dull. 
As for that recording of Mahler 3 with CSO. I’m assuming you’re talking about the Resound release? That’s actually my favorite recording of the work. Maybe the “recording” sounds a bit dry, but the sound is there. The opening with the horns is intense and bright, with great attack. The posthorn (cornet is this case) solo in the 3rd Mvt is as wonderful as it’s ever been performed.  The strings and winds throughout play with emotion that comes through on every note. Really my only criticism is the trombone solo in the 1st being a bit too herky jerky, having heard it performed in Philadelphia by the wonderful Nitzan Haroz. 
I offer another example where most orchestras including Budapest just can’t match the top orchestras. Mahler 9. It is such a wonderful work, but must be treated with care. Budapest plays the notes on the page, but that’s not enough. In contrast, the more recent recording of Dudamel and Los Angeles is divine. It’s hard to put your finger on it, but it feels like they play every phrase just a bit longer than the page says, giving it this sweet, flowing character. Everything is rounded, and this brings a connectedness not found in other recordings. 
Like I said, if you’re just listening to a recording for how closely it matches the live performance, you’re an audiophile. I get it. When it comes to orchestra I care about that too, but I care far more about the performance. I want to hear how the very top musicians perform these works. The conductor is but one person. The manager, for sure, but an otherwise much less talented team is not going to perform a miracle.