I have no problem getting yotes to coming in with a distress call but have yet to coax one in with a howler. I even bought a tape for it. Still seem to scare them more than make them curious enough to come looking.
I think that it's a lot tougher to call them with a howler. Now you're trying to talk their talk not just sound like food.
I've done it only a couple of times just for the heck of it but I don't normally. The couple that I've called in have been more curious and hung out around 150 yards or so. Unlike the rabbit calls where they run right into your lap. They certainly come in more cautious with a howler from my limited experience with one.
Then again, using one of these in the spring when they're all pair up is probably more effective if you know how to talk their talk... which I don't.
I bought one recently but havent used it in a hunting situation. I am just trying to get the hang of calling with it. I'll try it sooner or later. But for now the distress call gets them in...:shootin:
I use a howler almost every stand. Since I an not trying to call bobcats or foxes, I usually start with a couple of greeting howl. Then improvise from there. Here is a link to a couple of example stands: