AWS EBS are great and cheap option for storage, however it is network storage device so will not provide the same latency as storage directly connected to your physical hardware. An AWS EC2 Instance Store is actual storage directly connected to the hardware running your EC2 Instance and provide superior performance over the EBS. Instance Store is ephemeral storage type and if you stop the EC2 Instance you will lose the storage. Thus, Instance Store is not suitable for long term storage but excellent for buffer, cache, temporary storage solutions. Instance Store is also only physically connected to your single physical device and loss of the device would result in loss of data. Backup and replication of Instance Store is the AWS customers responsibility and not guaranteed by AWS.