My use cases:
I use these goosenecks (I have 4 of them) either for having a second mic on one stand, clamped on a board for instruments like koto or monochord, or mounted on a table stand for elevating the mic for instruments played on the floor, like a hang (it saves some space, compared to a mini stand like the Millennium MS 002).
Weight limits:
In the last case, where the gooseneck is basically vertical, I can mount mics like ATH 2020 or MXL 770, otherwise the weight of a Shure SM 57 is the limit.
Also consider that with a SM 57 the gooseneck will bend downward a few centimetres, when fully stretched out horizontally. You can make the system more rigid by bending the gooseneck, but you will loose about 30% on the maximum length. Otherwise, with mics like Rode M5 and t-bone SC 140, there are no problems.
Durability:
After using them about 30 times the rigidity seems to have not changed, though this is a subjective feeling spread over one and a half years of usage.