Commercial printers using SLS and printing in nylon (predominantly) end up having products that are every bit as strong as the injection molded counterparts. The nylon is literally fused together layer by layer. Home printers will vary depending on how much tinkering with their machines the owner has done. There are also a lot of other parameters that the printer can play with such as layer size, speed of extrusion, infill percentage, etc. all of which contribute to the overall strength of the finished piece. The home user has to also factor in just how long a single print will take, so they usually make compromises to print faster. That's why I only use a home printer to prototype and not to produce anything I would give or sell to someone else. I use mounts I designed printed by
Shapeways and I carry about $400 worth of camera equipment with me on nearly every ride.
If you can't design your own stuff, then you are at the mercy of how someone else wants to build their items. I do have a lot of small parts up on Thingiverse is you want to try printing them yourself. Just note that the free stuff, at least in my case, is lower resolution and usually the first working models that I create. Then I go through a lengthy process of refinements and reprints until I have something that is light and strong. I do not go back and update Thingiverse with all the latest designs changes unless there is a significant functionality difference.