What’s your primary use. Games or music?
I've had both and the G6 was good for games. But I really can’t stand creative stuff because of their drivers. K5 was better for music. Seems to have more power behind it. Wasn’t blown away though.
I am using a Topping a50 / E30 stack at the moment and it’s noticeably better than both. But it obviously does cost more so not a trait comparison.
if 7.1 isn’t something your interested in get the K5. Or keep checking for refurbed G6 on creatives site or the bay. They come up all the time for £65 or so and for that it’s a bargain. Even with the carp drivers.