they work, generally. they're as imperfect as most of us.
they're wide. (wider when mounted than the System Cases on my BMW GS.)
shape is odd. not only does this require some creative packing, but the convex shape of the lids causes the brushed metal part of the case to be a primary point of contact on things like (garage) doors.
latch to open them is odd, requiring that you generally use 2 hands to open the dang things. getting it one-handed is not impossible, but it's a trick.
locks are fiddly to set up due to the *tiny* springs in them, but doing it patiently over a towel makes it possible. keys/locks are quite stiff initially, but seem to loosen up.
it's nice that you can mount the cases and choose whether or not to have them locked securely shut or unlocked for ease of access without the key.
they do cause some drag, noticeable mostly on in high-speed roll-on.
a mild wobble seems to be induced at extra-legal speeds (validated on a closed course, naturally!) when loaded on a 1090, but i haven't experimented to verify that it's not possible to eliminate by fiddling more with preload. KTM sells a floating mount system that's supposed to address this, but i have not yet tried it.
one of the seals on mine wants to fall out about half the time when i open the lid; it hasn't been enough of a problem for me (yet) that i've looked into securing it better.
there are mesh nets inside the cases and the lids that are not readily visible in most pictures i've seen online, which come in quite handy since the clam-shell design means that everything wants to fall out when you open them up. (note: this is less of an issue when on the center-stand, if you have one...)