I have used both, and according to instructions for the keeper you can trim the stem. I couldn't get a "smooth edge" though.
My biggest reason for switching, however, is the fact the keeper has latex in it. I am an RN, and am exposed to lots of latex on the job (gloves, etc). The last thing I wanted was to expose such a sensitive
area to latex! An allergy, if it got severe, would be a hassle on the job
I use my keeper on the heavier days of my flow, with Lunapads backup, as well as just lunapads pantiliner/minipads when my flow is spotty/light.
An aside...how do you all clean yours? I have been getting a mild yeast infection every month just after my period, and I have done everything I can think of to prevent it, also even dh and I were treated with oral meds. I am suspecting it may be from the cup. Do you use vinegar or boil it or something?