I personally find that the membership fees are often not high enough to warrant not becoming a member if you're planning on flying with friends on occasions and want to share legs.
I also personally find that check flights are never wasted! Yesterday I did a check flight in a plane very similar to the one I normally fly, but it had slightly different start procedures, and when I got to the PFL, having not done one for over 3 months in this type of plane, it was really good to be reminded of a few tricks that you can't use on the slower planes I have been flying during the summer.
Every flight is an opportunity to learn and become safer - why not take the hour checkout? If nothing else it'll make sure you're comfortable in their plane!