Laptops

Performance increase should be significat compared to currnet configuration. It is recommended for both drives to tick at the same speed but for raid 0 to work it doesn't matter if hdd-s are at different speed.

I personally would not recommend doing RAID 0 in your situation. The point of RAID 0 is to increase performance, yet you have two drives with seperate speeds. It then becomes a question of how your RAID controller handles this. Along with the fact that if one of the drives fails, you lose your data. If you are going for speed in a laptop, I would recommend picking up a solid state drive for your OS and using the other drive for data.

I think it comes down to what you are trying to accomplish. RAID 1 might be more beneficial just from the data standpoint, if a hard drive fails, its already mirrored on the other. No matter what scenario you go with, you should back up your important data to another source. If the laptop to lost, stolen or damanged, you are out of luck.

If you value your data at all, no. Any disk failure (and the disks in one's laptop are not first quality) and it ALL goes away.