I've only experimented with them as I'm still building the layout. But yes, I found that you often have to use a good bit of force, or use the uncoupling stick to move them side-to-side a touch to make sure they are coupled.

I'm on the fence about whether I will use them. Initially I was not planning on sharing any equipment, but now that I'm modeling steam a friend and I will be sharing locomotives at the very least.

Since my primary modeling purpose will be operations, we will probably go the Kadee route and clip off the 'air hose'.

If we do go with the Sergent's I have also found that the ones I assembled don't work as smoothly as the pre-assembled ones.

Randy Hammill
http://newbritainstation.com