Some reviews and people have said the drive cages feel loose but to me once drives are in and snapped in they feel tight enough. With the stock fans and the filter on, during parity checks the drives will go to 50C depending on location. If you remove the filter it will help tremendously. I switched them out for Noctuas because my motherboard only supports PWM fans. For me, if the fans are set to auto my cpu/system doesn't get hot enought to spin the side fans fast enough to cool the drives. I set them to a specific value and they run at 800-900 rpms and my rear runs at 600 rpms with auto. Drives are close to or below 40C. I also drilled out a bunch more holes in the drive cage and especially in the plastic gpu piece. As far as backplanes I don't know. I won't be poppin drives in and out all the time.
Also I noticed some reviews complaining about cable management with a wad of cables shown between the motherboard and 2 side fans completely restricting air flow. For my setup, I wrapped the fan and case cables around the side fans, extra power cables fit above the backplane and power supply, sata cables fit behind the backplane and below the power supply between the rear fan and finnally my motherboard atx cable comes up off the motherboard and behind the backplane. This leaves an empty void and direct path from intake fans to backplane and motherboard to rear fan.
Those drive temps seem fairly high to me. I'm used to seeing temps in the mid 30's and anything above mid 40's worry me.
I don't think the backplanes fail from inserting the drives. It seems to me that most backplanes, in general, fail because the pcb traces weren't designed to handle the current load of the drives. Designers often fail to consider the current of drives during startup.
For anyone into modding cases, I wonder how difficult it would be to cut out the right side panel so that the air flows right through the case from one side to the other. I highly suspect that is the reason for the high temps. It is difficult to calculate the exact path of the air flow, but I'm suspecting the current design creates small pockets of stagnant air which prevents proper cooling of the drives. If anything, someone should try to measure temps with the right side panel partially open to see if it makes a significant difference.