1. Why did they put a label on the RAID devices? They should have just used /dev/sd[b-x] directly, and not confused the situation with a partition table.
2. Did they align the partitions they used to the RAID block size? They don't indicate this. If they used the default DOS disk label strategy of starting /dev/sdb1 at block 63, then their filesystem blocks were misaligned with their 128 kiB RAID block size, and one in every 32 filesystem blocks will span two disks (assuming 4 kiB filesystem blocks).
3. Why did they use md and not LVM? md can sometimes introduce bandwidth limits, and LVM lets you alternate between striped and linear volumes for your testing.
4. Why don't they report the raw bandwidth of the disk, and maybe some IOPS numbers?
5. Why don't they report total operations and bandwidth consumed as measured by iostat or sar?
6. Why didn't they give geometry hints to mkfs? The ext4 mkfs invocation, for example, should have included "-E stride=$[128 / 4],stripe-width=$[(10 - 2) * (128 / 4)]".
7. What about using an external journal?
8. They report that "during the file system check the server did not swap, and no additional use of virtual memory was observed." Wouldn't it have been better to just do "swapoff -a" and report that no swap was available?
9. Why didn't they (as someone else also suggested above) test an actually damaged filesystem?
10. Is there any indication other than their credentials that these people know what they're doing?