UncleDave :
In the worst case scenario the different timings can cause a skip in data writing which will render the data useless.
I hardly think so. No error will ever arise from using mismatched drives unless there is a hardware problem.
Using mismatched drives will work fine with no errors. However, there is a performance degradation.
For example, say I build 3 different 2-drive RAID-0s, one with 2x drive A, one with 2x drive B, and a third with 1 each of A and B.
Let's say drive A has better and more intelligent cache handling, and therefore outperforms drive B with several requests for small files. But drive B has a higher sequential transfer rate (STR) and outperforms drive A when reading large files.
My first RAID-0 with 2x drive A performs much better than the second RAID with 2x drive B when reading several small files, thanks to the better caching in the A drives.
My second RAID-0 with 2x drive B outperforms RAID-0 with 2x drive A when doing Photoshop scratch work, thanks to the higher STR of the B drives.
The third RAID-0, with 1 each of drive A and B underperforms both of the other RAID-0s. In the several small files case, the RAID controller is always waiting on drive B to complete requests because it's caching isn't as good. In the STR applications, the RAID controller is always waiting on drive A to complete requests because of the slower STR. In short, the 1 drive of each RAID is always hampered by the worst-case performance of any single connected drive.
This is why it's generally recommended to use identical drives. Since the purpose of RAID-0 is to increase performance, and using different drives hampers performance, the use of different drives in RAID-0 is counterproductive.
For other RAID levels, like RAID-1, it's less counterproductive, but the performance still suffers.