Raid 5 is not hot swap, thats a term that depends on the server hardware (hot swap means you can replace failed drive without even powering down the server). Raid 5 can be configured to have a 'hot spare' (an unused disk drive on standby ready to take over if a drive ever fails so you dont loose performance very long after 1 disk fails). But you still have to power off the server to physicaly replace the failed disk unless the SERVER is hot swap enabled.
You need more than 2 drives to achieve raid 5, which usualy means you are already outside the 'size' of a standard leased dedicated server - so if you want raid 5 eventualy make sure you ask how many disk drives you can fit max inside the server, or if building your own to colo with just be sure its the right size.
Raid 5 is better than raid 1, in simple terms, due to higher performance (spreading the load out across many disks) - but both give you redundancy/backup potential if 1 disk drive fails. Raid 1 is your only option if you are in a standard 1u server case with just 2 disk drive capacity.