Quick take
JIMMY R9 is the value hot-water alternative. Waterdrop K19 is the lower-cost purification-first alternative. Under-sink RO is the better choice when countertop space and hot/cold dispensing are not priorities.
JIMMY R9
JIMMY is attractive when hot water matters but chilled dispensing and the U1 premium are harder to justify.
Waterdrop K19
K19-family products generally cost less and focus more on purification than on premium appliance features.
AquaTru
AquaTru remains a strong evidence benchmark for shoppers prioritizing certification over hot/cold convenience.
Under-sink tankless RO
For homeowners, Frizzlife or Waterdrop under-sink systems can free counter space and deliver higher continuous flow.