I have seen both of the cases. In my humble opinion, is better to have the partition. Windows keeps some files there that will improve the boot process. And if you have two HDDs this partition should be on the drive that NOT contains the OS (unless you are planning to retrieve one the HDDs) for increasing performance. But be carefull, if you remove the disk in which the reserved partition is, your system will not boot.
Suppose I have created System Reserved partition. Now when I have to format windows 8 then what will be?? Do I have to then delete System Reserved partition and the main partition and have to recreate patition?? because manually System Reserved partition cant be created, it will be created by win8 setup at the time of partition creation. What is your opinion?