Here is our experience:
One member was coming back each month and joining with trial to get past month's updates and canceling right away. When we took down the trial option, he joined for 3 Months!
Currently we only have monthly joins and we are using a join page only exit console to offer trials, which is only triggered once they go away to another site or close the window. And our "trial to full" conversion ratio with those joins much better than the previous.
I hope that helps
