I have been using this ball head for 3 years; and it always delivered. I usually do landscape and astrophotography with this ball head. I found it surprisingly good with little to no sagging. I shoot regularly with a friend who uses the RRS BH-55 and we compare the two quite often. Based on our findings, there is no performance difference between the two. Can't confirm that in cold weather, I shoot 98% of my photos in Hawaii. However, I took this to Yosemite (40Β°F) and to the top of Maunakea (30Β°F); It worked smoothly and flawlessly as I expected. The largest lens I used was a Tamron 150-600mm. There was a slight misalignment when tightening, but nothing major to be honest. My gear: Canon 5D Mk3/Canon R5Tamron 15-35mm/Sigma Art 14mmGitzo GT3531 MountaineerDesmond DLow-55