Coincidentally, I put the Inbal M4 and M5 in my car yesterday, along with the Rattle M3. It has been a long time since I listened to any of these recordings, and I just finished listening to the "surprisingly" excellent Inbal M4. I really couldn't remember much about either of the Inbal performances, and Vatz' revisiting of the Bertini box had me wondering how competitive the Inbal box would be. I'll post my impressions of his M5 in a couple of days.
As for the Maazel, I have a general rule for Mahler: avoid Maazel. His Mahler is generally stiff, mannered, and slow. His VPO M4 has Kathleen Battle, which is the only thing that makes it a must-own. His VPO M2 is a good effort. As for this thread and his M5, it is stiff, mannered, and devoid of any tension -- avoid at all costs (do not be sucked in by the bargain price).
The Bernstein/VPO is easily a top choice. I also consider some of the other ones previously mentioned to be my first tier favorites: Tennstedt/LPO (live, not studio), Solti/CSO (70's analog/studio, not 80's/90's live digital), and Mehta/NYPO. The Solti is a rather aggressive reading, but it was the first M5 that I really liked (the first one I ever bought was actually the dreaded Maazel).
Others that I put in my first tier of favorites are Chailly, Karajan (see recent thread), and Boulez -- all off the top of my head.