Depends.
-If it’s for ROMs only, then id use a MicroSD card as it’s cheaper and meets the needs
-If it’s for games within the past 8 years, I’d go for the SSD upgrade.
One thing I’d note, if it’s the SSD upgrade, I’d save and splurge for the 2TB NVME instead.
Is 30g really that big of a difference to you people?