Besides RF power level: Some have LED indicators only, some have analog meters, some have digital meters, some have both analog and digital meters, some have an internal balun, some have just a single output, some have more than one output (switchable), some have more memories than others, some have an internal biasT for remote powering through the coax.
Phil - AD5X
And some have no indicators at all! That definitely saves some cost, and the tuner doesn't need an indicator if you already have one.