The m3.large pairs 2 vCPU with 7.5 GiB of RAM, the 3.75 GiB-per-vCPU ratio that marks a general-purpose instance. In the name, "m" is the general-purpose line, "3" is the generation and "large" is the size within the m3 family. It runs on Intel Xeon E5-2670 v2 (Ivy Bridge/Sandy Bridge) at 2.5 GHz, and AWS introduced it in January 2014. AWS has since shipped m4, m5, m6i and m7i; m4.large is the direct replacement at this size. gp.vs1.large is the closest Spot shape: 4 vCPU and 16 GiB, so 2 more vCPU and 8.5 GiB more memory, about 92% below the US East (N. Virginia) on-demand rate.
Match qualityNo local disk
m3.large comes with 1 × 32 GB SSD attached to the machine. Rackspace Spot nodes use network storage only, so that disk does not come with it.
If you were using the local disk as fast scratch space — temporary files, a local cache, an index — you will need a persistent volume or object storage instead, and both are slower to read. If it was just extra space you never depended on, nothing changes.