S2 Mini vs Solo?

[mcarr114]

Hi. Apologies if my question is too basic or obvious, but I've tried to compare and cannot find a conclusion. I am designing a new board based around an S2 SOM, and don't understand the difference between the S2 MINI and the S2 SOLO, other than the mini being a slightly smaller footprint. Other specs seem to be the same, and costs are nearly identical. Could you kindly help me understand why one would choose one over the other? Thanks much.

[MicroController]

The difference seems to be that the MINI has fixed 4MB of on-chip flash, while the SOLO is available with up to 16 MB flash on the module (which allocates one more GPIO pin, and more PCB space).