The short version
Both are handheld red light devices under $300. LightStim is the FDA-cleared decade-long clinical reference. Solawave is the budget multi-modality consumer entry.
When LightStim for Wrinkles is the right pick
If you want FDA-cleared handheld red light with peer-reviewed clinical evidence on the specific device — LightStim is the right shape. Four-wavelength coverage, documented dose, 1+ decade track record.
When Solawave Wand 4-in-1 is the right pick
If you want budget entry to red light with multi-modality consumer stack — Solawave is the right shape. Single red wavelength, modest dose, but the LED + microcurrent + warmth + massage bundle is solid consumer value at $169.