What about Gradient Lag?

Snap!! Did exactly the same. Personally I prefer the wahoo unit. Yes the Garmin has more Bells and Whistles on it but as I only use about 6 or so basic data fields I want them to work properly and for me, the Wahoo does this perfectly. Furthermore the recently announce Summit Freeride feature which both GP Lama and DC Rainmaker have reviewed looks to be every bit as good if not better than Climbpro, So until Garmin gets its finger out and fixes some of these basic issues, I will stick with the Wahoo.

Well, the GPLama touched on this in his comparison review, and unfortunately the 840 and 540 have identical problems. So whatever hardware problem the 1040 may had introduced, it is continued in the more recent models. 

I, personally do not think this is hardware problem but the more holistic approach to gradient calculation of Garmin. Why they are not fixing it, this is another issue...

If you are happy about/with your Wahoo unit, then great for you. I still don't understand why you guys always have that big need to communicate this.

Just use the device you like most, that fits your needs most.

actually to show am/was in same boat and to maybe help other cyclists ...not in an braggy way but just letting others know there is a way.

If you know how software companies work these days it is obviously a priority decision. This has no priority on their side.

Now it might be that their user research is garbage and they don't know how to set the priorities right. But I doubt this with a company in that size.

Regarding your Climb pro issue

AndyThomas said:

Sa Calobra I had to go about 500m downhill at the end to get it to complete

This GPLamma video may explain what happened https://youtu.be/EafiUo9ur-0 

Because Climb Pro uses the elevation data from the loaded course not from the device, if that course came synced from Strava to Garmin connect it can get corrupted and the Elevation data and GPS is out of phase which can cause exactly what you saw over the top of Sa Calobra. 

GPLama solution:

"The summary is that some routes syncing from Strava to Garmin Connect may become 'stretched' or phase shifted resulting in an extremely poor performance with ClimbPro. Loading the GPX directly from Strava into the Garmin EDGE is the solution for now...."

Mine was loaded direct from Strava I'm afraid. I'd watched that video before I went away hoping it would solve it 

Happy with workarounds, but this doesn't do it for me

And like the gradient lag I'm sure Garmin will now say "this is within the expected margins"

baselpower Unlike you - I believe It’s important to everyone involved, to be aware that Wahoo units work amzingly well in reporting grade.

Here's the deal. Complaining on this page does absolutely NOTHING!!! If you want to actually be a heard then you need to go here https://www.garmin.com/en-US/forms/ideas/ and flood them with this issue. I have sent a few regarding this but more needs be sent.