I use the click bushing die in 6.5CM. Came with the five different bushing size kit with it, I've used three of them so far and everything looks good and fits together correctly. I get consistent sizing if I run the cases all through at once without taking the die out of the press. After the die is removed and put back in later it's been within 0.001" repeatable, which is notionally inside the click adjustment range so the lock ring is holding correctly. The click function is helpful but not a game changer. The headspace comparator it comes with is better than Hornady IMO, I appreciate that they'd include that with a die.
For the above reasons I would recommend it as an upgrade over a FL die, but I'd also say it's not different enough to justify the cost if you already have a quality FL bushing or bump die. I would have more use for a Redding mic neck bushing die for a bench rifle because I can get similar shoulder bump from other dies, and the Whidden die isn't any better at managing the length of neck sizing than any other bushing die with a non-mic stem for the bushing.
I have not used a Whidden seating die.