5. Parallelism
On-disk: When you query an on-disk table that has a columnstore index, the database engine can use parallelism to process the results more quickly.
Memory-optimized: When you query a memory-optimized table that has a columnstore index, the database engine can use parallelism to process the results more quickly, BUT, that statement is only true if you use interop. Natively compiled modules are always executed serially.
Click through for the rest of the comparison points as well as a repro script.