Tend to go whatever’s on cheapiest at the time around LX level on my Shimano drivetrain equipped bikes so Shimano HG73 or SRAM 971 then use a gold Powerlink…you can use Powerlinks with chains other than SRAM with no problem.
A chain is a chain, the more you pay, the nicer it will look, and lighter it will be, there won’t be much difference in functionality though.
What alternative to a powerlink are you looking at? KMC and SRAM and others are all virtually the same design for 9 speed, only Shimano with their proprietary pin are different, all systems work well, but the powerlink is easier if you need to undo the chain, as the Shimano is single use, and the powerlink for 9 speed is re-usable.
You can pick up PC951’s or PC971 for £9.99 or PC991’s from £14.99 which are nice and shiny.