I've listened through Gergiev's LSO M7 twice now. While I certainly won't call it "the best" in my collection (I like the 7th), it's very much a welcomed addition for me. The tempi are definitely on the fast side - 72 minutes in total. As with the Gergiev's M6 and M1, there's a fair amount of bluster in the louder passages. But it's also easy to detect a guiding intelligence behind all that bluster. For example, in the back half of the first movement, Gergiev really plays up the bizarreness of Mahler's writing. It's as though Mahler were making parody of late romantic music; the over-bloated Austro-Hungarian Empire; and, himself (really loud cymbal crashes throughout this passage). But he then slows down greatly for the two measures that have an obvious funeral dirge rhythm in the drums and low brass (while the horns play the main theme in their middle and lower registers). This two-bar dirge is located just before the final peroration near the end of the movement. Anyway, this is a truly astute touch on Gergiev's part (and a big complaint I had about the MTT/SFSO M7 - the fact that he just blazed through the same two bars). Earlier on, Gergiev/LSO do a really nice job with the contrasting, moonlit episode that occupies the center of the movement. It's certainly done far better than on MTT/SFSO (and yes, I prefer MTT's earlier LSO M7 to his S.F. one).
What I find really interesting is Gergiev's tempo relationship between the first Nachtmusik (2nd movement) and the scherzo. He takes the first Nachtmusik very swiftly; a bit less than 14 minutes. At times, it sounds more than a bit impatient, such as the brief "tango" passage towards the end of the movement (a sultry tango melody in the cellos, accompanied by tango rhythms from everyone else). But while Gergiev's Nachtmusik I moves in a fairly flowing 4/4, his scherzo moves at a relatively slow 1 beat-to-the-bar (if you were beating in three; then yes, it would be faster than Nachtmusik I). In other words, Gergiev heeds Mahler's instruction not to take the scherzo too swiftly. It's an interesting switch.
In contrast, both Abbado and Barenboim take over 16 minutes for Nachtmusik I (wonderfully atmospheric at this slower pace), but then speed up greatly for the scherzo. I think Gergiev's approach makes the scherzo sound bigger and more important in the grand scheme of things. He also doesn't have to slow down greatly for the second subject - a frequent happening that Mahler doesn't really ask for (oboe melody accompanied by strange sounding trills). Perhaps it's not an improvement, but it is an interesting switch.
Within this scherzo, Gergiev does nail many of Mahler's deliberate sound effects, such as the nasty snarls from the tuba (scary things popping up out of nowhere in the night), and the two famous snap pizzicatos that are the true climax of this movement. I sense that this is what Mahler really was looking for in this shadow dance of a movement. I really like the last two movements under Gergiev's direction.
Both Nachtmusik II and the finale are quite fast (11:45 and 16:13). I really like these tempi. Nachtmusik II is lent more the atmosphere of an Italian serenade than usual (sufficient mandolin here), allowing for a perfect transition into Gergiev's blistering finale. While Kondrashin/Concertgebouw is more cleanly played (also very fast), Gergiev brings out more of the cowbells and deepbells towards the end of finale. The whimsical passage with the simultaneous bass drum and cymbal strokes is terrific. My only complaint is a minor one: the LSO's Paiste tam-tam speaks too slowly for many of the rapid strokes that happen in the finale (Paistes are used almost exclusively in London, by the way). A good Wuhan tam-tam has a clear advantage in M7.
Anyway, say what you will about Gergiev, he at least plays to the strengths of the LSO - the one band that has always been considered to be the sleek, lean race car amongst London's five full-time symphony orchestras. When I was much younger - several decades ago, obviously - I dreamed of hearing or owning an awesome Mahler 7th from the LSO. "Star Wars" had just hit the big silver screen, and I wanted to hear that Star Wars brass section in this music. Well, the final results may not be any better - or even the equal - of those that you get in Amsterdam, New York, Chicago, or Berlin on truly great days, but it is fun to hear the LSO's brilliant brass and percussion have such a field day at Mahler's expense. At the very least least, I'm sure that Mahler would cheer such a fiery presentation of his most brilliant finale.
Timings are I - 20:47; II - 13:43 (very fast); III - 9:07; IV - 11:45; V - 16:13