[Yes] I changed my camera from Canon DSLR to Sony mirrorless.
I also considered FSB4 to be lighter than the FSB8 fluid head that I was using, but I found this ACE-XL head and purchased it.
I am trying to reduce the weight by attaching this head to a Gitzo type 3 tripod.
This is 1kg lighter than the FSB8, yet the payload is 8kg.
Even with the combination of 600mm F4 + A9, it still works with a great balance.

[Yes] This does what it's supposed to do. The previous negative review is from a user has no clue what it was made for to begin with and should be removed from B&H as completely inaccurate

[Yes] I got this amazing gear to complete my Dana Dolly System and it is the perfect solution for my needs! Solid, professional quality build - it enables me to get the shots I plan - every time! When you want reliable, trustworthy gear on your set - get a Sachtler!

[Fluid Head] I wasn't sure what to expect, as this was my first video fluid head purchase. Being relatively cheap compared to other Sachtler offerings, I was also not quite sure what to expect. With that being said, after using it with my Blackmagic Pocket Cinema Camera 4K, it is absolutely wonderful. So smooth. The fine tuning adjustments are top notch. Would absolutely buy again, and would absolutely recommend.

[-80° to +90°] The other reviews on this head are unfair and not accurate, in my opinion. We've used an ACE L fluid head for almost 2 years and are very pleased with its operation, counterbalance and smooth panning/tilting. The composite material has held up perfectly well. We looked at competitive heads and bought the latest ACE XL instead - a vote of confidence. The buyer should be aware that with the extended payload range of the XL versus the L that there is no longer a 0 setting for counterbalance, and the unit is rated for 2-8kg versus the L which was rated for 0-6kg. The lowest counterbalance setting of 1 on the XL is similar to the setting 2 on the L. This is less of an issue than it might sound like since the 0 counterbalance setting on the L seems more useful for setup than operation, and neither head is ideal for tilting a truly light camera setup (naked mirrorless with prime lens). I was tempted by the lure of continuous counterbalance adjustment, but found that the repeatable workflow offered by a decent number of discrete settings is superior in the real world. My experience with the less expensive competitor mentioned by another reviewer were very negative, leaving me to wonder if the discrepancy is due to significant variability in quality by that manufacturer or simply lack of discernment by the review. Ultimately the real value in the Sachtler Ace heads is the combination of impeccable results which they are able to provide and the great price point.

[11.595 lb] I've been using the Manfrotto 504HD for about 10 years or so, and it felt like it was not as responsive in terms of panning, but especially tilting. I did a lot of research and Sachtler Ace XL was the one that most of the videographers recommended at this price point. I put it on Manfrotto Carbon sticks, and man, what a difference in every aspect! Tilting and panning are silky smooth, but most of all, the WEIGHT!!! The 504HD I never realized how HEAVY it was until I started using this Sachtler. Of course, my additional Carbon sticks are super lightweight, which made it even nicer! I would highly recommend this fluid head if you want to 'upgrade' from Manfrotto fluid heads within this price range. You will not be disappointed.

[-80° to +90°] The best solution with a low budget

[11.595 lb] I purchased this head nearly 10 years ago. It has survived trips all over the world and three cameras later, it is still the same as the day I purchased it. Smooth action with no perceivable backlash and flexible counterbalance system. It is now the heaviest item in my camera bag as I now use it with primarily a DSLR to shoot my video. Sadly hasn't been used much recently due to the state of travel with the coronavirus, but will hopefully be on the road again soon.

[Fluid Head] I'm a nature photographer that shoots exclusively stills (no video). I'm presently using a Sony Alpha 1 camera body and, mostly, a Sony 600mm f4 GM lens. I have tried a number of tripod heads and I know most nature photographers use a gimbal head when using long telephoto lenses. I had been using a Sachtler FSB8 fluid head with a Gitzo tripod and found it superior to any gimbal head I have tried, and I've tried many. I decided to try this Sachtler Ace XL Fluid Head because it's about 2 pounds lighter than my FSB8 head. I like it almost as well as the FSB8 head. For my setup, the drag setting selections are to my liking. Even though I own the more expensive head, I find myself exclusively using this head in the field because of its lighter weight.

Since all my lenses use the arca swiss clamping system, its too bad Sachtler doesn't offer an arca swiss top clamp rather than having to add on an arca swiss clamp to their clamp. (I removed the thumb screw that locks their slideable clamp mount and replaced it with a metric hex bolt of appropriate length so as not to mistakenly turn it when reaching for a different knob. The sliding adjustment range is sufficient with the arca swiss clamping system.)
The only thing I don't like as well as the more expensive FSB8 head, is
the bubble level is harder to see without turning on its light.

Being similarly priced to a top quality gimbal head, I fail to see why more nature photographers shooting stills don't use this fluid head with a 75mm bowl to permit smooth bird-in-flight tracking and quick leveling during setup.

[-80° to +90°] The Sachtler Ace XL is a great fluid head. I've used this it for over 2 years now. It's been used in the rain, snow, heat, traveled in countless check bags around the country, and it still works like the first day I bought it. It handles sony alpha series cameras to a red scarlet-w. I moved to this from a head without the ability counterbalance and it's a gamechanger. The Ace XL is nice and small but strong enough for most cameras. I definitely recommend Sachtler.