Conclusion
In terms of data transfer speed, the differences between these three controllers are not that significant. It is more convenient to choose fast hard drives rather than to consider the many aspects of RAID controllers. However, this picture changes as soon as you take application performance into account. Here, Promises FastTrak100 TX2 is able to break away from the two competitors, as it performs superbly, even if you use RAID 0+1 setups (striping plus mirroring). In addition, the Promise manual is more comprehensive than the AMI manual.
Motherboards with an on-board HighPoint RAID controller usually don't come with an extra manual that explains the controller features and configuration. In this respect, all three products are quite easy to handle, as they offer convenient BIOS versions to set up your desired RAID mode.
Following the recent acquisition of the AMI storage division by LSI Logic, we will have to wait and see how prices for the MegaRAID IDE 100 will develop. Currently, the FastTrak100 TX2 by Promise is the most expensive solution. HighPoint's biggest advantage is that their products are widespread, thanks to the integration onto motherboards.
Given the choice of buying either a motherboard with integrated RAID or a simple model plus additional RAID controller, I'd definitely take the integrated solution. First of all, the performance difference is usually not noticable. Second, integrated solutions are cheaper, and third, you can still disable on-board devices and use something else (e.g. future ATA/133 RAID adapters).
