I’ve got the 504HD for my HPX170 and I use it with a mattebox and a rail system. It really does hold the weight well. Manfrotto stepped up their game on this one. The FSB4 is a fine tripod and it is a Sachtler but at that level of tripod I don’t think you’re getting what really makes Sachtler great. Above that, the FSB4 only holds 8.8 pounds as compared to the 16.5 pounds that the 504HD can handle.
In the end, a tripod can seriously outlast your camera if you treat it well and you look ahead. If you ever decided to add weight to your rig or upgrade your camera, the 504HD will give you significantly greater flexibility over time.
Panasonic HPX170 P
2008 Unibody Macbook Pro 15 inch, 2.8 Ghz, 4GB RAM
CalDigit VR
Final Cut Pro Studio 3
Avid Media Composer
The College of WIlliam and Mary