Quick take
Choose RKIN U1 for a more premium hot/cold all-in-one experience. Choose JIMMY R9 when lower upfront cost and hot-water convenience matter more than chilled dispensing.
Core use case
Both are no-permanent-plumbing countertop RO systems that work well for renters, offices and buyers who want appliance convenience.
RKIN U1 strengths
RKIN U1 combines RO with hot and chilled water plus remineralization-oriented features, placing it in a premium tier.
JIMMY R9 strengths
JIMMY R9 is priced materially below premium hot/cold competitors and emphasizes quick hot-water dispensing and countertop simplicity.
Ownership cost
The decision should include annual cartridge cost, not only equipment price. Proprietary filters are the main long-term cost for both.