Testing WAS done in our back yard,

without realising that some biners cause a repeated savage lock on raps. Fuzzy vs new ropes made no difference.

Full testing should have been done by Edelrid before releasing the device.

who is not descending (e. g. by means of a knot).
11.Abseiling:
For abseiling we recommend to turn the securing device around so that
the thumb bracket points to the body (Fig. 11a). Additionally, use a Prusik
sling for back securing.
The rope can also be inserted in the securing device as described under
item 3 (securing a lead climber) (Fig. 11b/11c). For abseiling, the securing
device may be unlocked by means of a karabiner attached to the unlocking
eye. The unlocking eye is optimally adapted to the EDELRID Pure
Karabiner. If an unfavourable combination of karabiner, securing device
and rope is employed, the rope‘s run may either be inhibited or too fast.
Check the compatibility of the combination, using it in a safe environment.

My suspicion is that all three of the current crop of "alpine" assisted locking devices (the Mega Jul, the Alpine Smart, and the Alpine Up) were designed primarily to work with thin twin ropes, which are far more popular in Europe than in the U.S. and U.K., and the further you get from those sizes the more trouble you'll have with handling.

Doesn't the smart have two versions for different rope sizes?

"If an unfavourable combination of karabiner, securing device
and rope is employed, the rope‘s run may either be inhibited or too fast.
Check the compatibility of the combination, using it in a safe environment."

They have got to be kidding. How many people here would do their own testing for all their ropes, all their biners and all their belay/rap devices, before using them on a crag ? Next manuafacturers will be asking us to test their harnesses before we use them on crags ... that would have stopped the fellow losing his approach shoes when the gear loop on his Edelrid harness broke http://www.mountainproject.com/v/edelrid-mega-jul/108052298

My wife took 10 minutes on a 12m rap with the mega jul, because she couldn't get the thing to release. Getting stuck on a long rap could be a nightmare.

I'd definitely check out what works best with a new rap/belay device before taking out on a climb just to avoid something like this;
.

So did we ! Unfortunately we did no check all possible combinations of all our ropes, and all our biners. The combination we checked first worked fantastically well ... we were fooled !

Do you test the strength of your harness before using it ? Do you test under what circumstance trad gear will fail ? No. We trust that the manufacturer has carried out sufficient testing. Where there are dangers or limitations, there should be clear warnings, not fine print hidden in the instructions.

We trust that the manufacturer has carried out sufficient testing. Where there are dangers or limitations, there should be clear warnings, not fine print hidden in the instructions.

We trust that the manufacturer has carried out sufficient testing. Where there are dangers or limitations, there should be clear warnings, not fine print hidden in the instructions.

... is going to be at least "difficult" with fat and/or fuzzy singles.

While this might sound as I am defending edelrid at all cost, i can not let this stand here uncommented.

It is not hidden in the fine print, it is just a part of the instructions like everything else. And its the responsibility of the user to read those (or not).

The only things shown outside of the instrucitons, on the packaging, is belaying a leader and belaying a follower. No rappeling at all. The video linked with the QR code however does show rappeling, but as first choice it shows the classic tube mode with a prusik. And at the end of the video it clearly says "read the instructions".

And in the instructions, it says that some combinations can cause problems.

So it all boils down to the question: What behaviour is within parameters and to be expected, and what is not?

I did not expect that it would be that bad, but I did expect that I do have to do some testing to find out what works and what does not. To me it was obvious that an autolocking device that is also meant to be used with thin halves is going to be at least "difficult" with fat and/or fuzzy singles. And as disucssed in this thread it indeed is. However if i use it in classic tube mode, it works perfectly.

Maybe a difference between cultures? I, as a german, deem the american labelling madness utterly ridiculous. If I buy a coffee i expect it to be hot. Its friggin coffee! I see the fact that the cup has a label that tells me "warning! hot!" as an insult of my intelligence. Its the same with all the "climbing is dangerous!" labels on a lot of gear. I know that, dont need to tell me. If the gear is something that is not 100% known to me, I will consult the manual and the internet. But that will lead to a meta discussion that has nothing to do with the device at hand…

qwert

The Click Up (a friend has one) works well up to 10.

... The Tre Sirius was a far better concept but probably marketed at the wrong time, as Edelrid hold the rights maybe they will re-engineer and re-launch it though looking at their single rope version I´m not so hopeful it won´t be screwed up somewhere along the line.

It´s actually a bit of a blind alley in some ways as far as assisted braking goes since the additional force is fairly limited...

i use the alpine smart for everything as does everyone i know who has one

its provides some slip just like an ATC ... and requires a break hand

the biggest problem i see with assisted locking devices is the lack of attention paid to the break hand ... people taught with ATCs are VERY conscious of their brakes ... gri gris less so ...