I would prefer RAID 5 there since you lose less space, and I consider the performance better. With 2x1TB RAID 1, you lose a full terabyte. With the RAID 5, you lose only 500GB.
That said, each has its own advantages.
RAID 1 advantages:
All the data is redundant.
If one disk fails, you do not have any performance degradation.
Easy to understand.
RAID 1 disadvantages
Lose more space.
Does not perform as well as RAID 5.
Has to write everything to both disks...no performance increase on writes.
RAID 5 performance is better for reads, which is good for database applications.
Since you asked specifically about this, better at random read operations and writes since it can read/write from/to multiple disks, however this is also mitigated by having to update the parity information for each write, so the benefits are not as great as with reads. RAID 1 also can read from both disks, but limited to just two.
These advantages can be increased by adding more disks.
Easier to add more space if you run low.
RAID 5 disadvantages
Performance degradation with the loss of a disk
RAID has to be rebuilt when one fails and is then replaced.
There are surely more reasons that can be argued, but these are the main ones.