I can compare - trust me, they're quite different from each other. The earlier Simax one is actually the better sounding recording. Also, Jansons was far more willing to peak under dark corners and stare into dark closets during this earlier 2000 concert - especially during the first two movements. The timings for the first two movements are significantly slower here than on his recent Munich one. Since he contrasts tempi quite frequently within movements, there are moments where he even reminds me of Klemperer just a bit. For me, it's the middle movement scherzo that's a bit of failure on this earlier Simax one.
By that, I mean that it fails to make the requisite jump from darkness to light, especially as the movement turns almost comical towards the end. This is followed by a second Nachtmusik (fourth movement) that's a throw-back to the days of making it consistently over 14 minutes long in duration. That certainly emphasizes the more nocturnal aspect of the movement, but it also sort of ignores the almost "Italian Serenade" quality of the music itself. As a result, we're suddenly thrown into the brightness of daylight at the very start of the finale. It's little wonder that early critics of the work felt that the finale simply didn't belong with the rest of the symphony. But on the whole, the finale on the Simax one is really, really good. I prefer it to the finale on the BRSO one.
In fact, it scores over the BRSO one in terms of capturing the work's, "concerto for orchestra" aspects. To be specific, the Oslo players were far more willing to let their percussion department - who do a very good job, by the way - reinforce the climaxes throughout the finale. There's plenty of tam-tam wherever it shows up, and the deep bells/cowbells are very prominent at the movement's final peroration.
For me, the finale on the BRSO M7 is a bit one dimensional: mostly fast from beginning to end. The Oslo finale has a far better mix of tempo relationships. In that regard alone, it reminds me a lot of Abbado; only with more percussion.
For me, the bottom line is this: I like the Oslo one better for movements 1, 2, & 5, but prefer the new one for movements 3 & 4. Put them together - interpretively speaking - and you'd have a pretty darn good Mahler 7th.
Hope this helps.
Barry