I had clear for a year or so. Prior to pre-check, I could see significant value in it if you regularly flew out of the airports that it covers. I flew out of SFO T2 a lot and it was a nice timesaver, plus they escorted you right to the table to put your items down (also would get a bin for you). In DFW, they weren't at the most convenient checkpoint for me. On occasion I would move down a checkpoint to use it, but here they would just have you cut the initial line and then you would wait in a line for the actual security check (also this checkpoint had the nudescope while my normal one was just a magnetometer).

Now that I'm 100% pre-check, at most I wait 2 minutes at SFO T-2. There's almost no value to me in Clear anymore.

Love my Clear card
 

My two cents worth.
I fly enough to be PreCheck most of the time, but always use my Clear card. I fly from MCO and DEN and in both places it's easier and faster to use Clear as the Pre lines are getting longer now days. At MCO they usually put me into the Pre line if I have that on my boarding pass and I think Clear is adding that as a permanent feature at MCO. I literally chuckle to myself every time I go thru security using my Clear. :)
But admittedly, if you only want to pay for one, Pre is more widely used (I fly from DFW all the time too and only have used Clear once because of the location of the kiosk).