If you think of a 2 disk array.
RAID 0: will give you twice the read speed and twice the write speed of a single disk.
RAID 1: will give you twice the read speed and the same write speed as a single disk.
So for reading, RAID 1 will give you the same read speed as RAID 0.
However, RAID 0 will make the loss of the array 2 twice as likely, whilst RAID 1 will make the loss of the array half as likely.
Therefore RAID 1 is 4 times as likely to be available as RAID 0 (with a 2 disk array).
Whether this is done with HardWare or Software doesn't matte on a modern machine, there are pros and cons for both.
(Of course, RAID 0 is giving you twice the capacity when compared to RAID 1, just included for completeness).
LVM is advisable for use regardless of which type of raid you are using. It's far more flexible than disk partitioning and allows for the addition of further disks at a later stage.