For the past few years, I've been using my Gitzo Series 1 Mountaineer as my primary tripod. It served me well when my primary camera body was the Fujifilm X-T2, X-T3 and X-H1. Once I bought the GFX 50S to use alongside my X-H1, I became acutely aware of the tripod's shortcomings. The Gitzo Mountaineer Series 1 GT1542 is an excellent tripod. Combined with the lightweight Arca-Swiss p0 head, the tripod weighed in at just under 3 lbs and featured a very slim profile when folded down. The 25mm max leg diameter contributed to this slim profile, and while it works well with entry-level DSLRs and mirrorless camera bodies, the slim legs are just a bit too thin for a heavier, professional level body like the GFX 50S. Most people with a larger, heavier camera would be perfectly served with any Gitzo Series 1 tripod, as they only need it for single shots in adequate lighting. In my case, I use it primarily for landscape photography, astrophotography, night photography, etc... situations that require long exposures and/or multiple exposures for stacking, exposure blending or panoramas. This requires greater demands on my tripod as any movement between shots can ruin an exposure. It becomes difficult, if not impossible, to work with multiple, misaligned exposures in post-processing, thus a lighter-weight tripod can cause problems as any flexing will result in misalignment. While I haven't gotten rid of my Series 1 Gitzo, I recently bought a Gitzo GT3542 Series 3 Mountaineer.
Since buying this head, I've quickly learned to love it, especially after buying the necessary hardware that allows me to invert it as needed. The smooth design, reliability and light weight has helped it find a permanent home atop my Gitzo GT1542 Mountaineer tripod, supplanting the GH1382QD ball head that came with it.
Some first impressions after picking up an Arca-Swiss P0 Ball Head recently. Why? It's interesting. It's an inverted design so that the panoramic base is above the ball, ensuring a level platform for panoramic photography. Basically it eliminates the need for a leveling base. Combined with the 9oz weight, it'll reduce as much as 1.5lbs from my systematic tripod setup. I quickly discovered the reason for the weight savings: the base of the ball head is made of polycarbonate, most likely Delrin. The rest is made from either magnesium or aluminum, depending on the part. Regarding the design, it also has no protruding parts beyond the pano lock lever. The ball lock is performed by a rotating collar around the middle of the body, resulting in a sleek design. The ball is also aspherical, a feature used across Arca-Swiss' whole line, that increases friction to prevent your camera from loosely flopping over when the ball lock is loosened. A very elegant solution to a universal issue with all ball heads.