If you are happy with the ones you've got then why venture into unknown territory?
I have 105s. I knew nothing about clipless pedals other than some bits I read on bike forums and would possibly have been better with spds instead of spd-sls. However they have been great. About 8,000 miles in, no maintenance at all. The axles are slightly bent because of all the weight I have put on them and yet when I'm fettling or cleaning the bike I'm always amazed at how freely they spin when I give them a twirl. They would be top of my list for new equipment if I changed my bike.