I made a topic here with efficiency measurements of some drivers : Efficiency measurements of a few drivers
Unfortunately I don’t have that many flashlights especially from majors brands like Acebeam, Olight, Fenix, Thrunite… etc to compare them.
Zebralight gets often parroted as ”very efficient” but that depends on the model, the SC64 (XHP35) is not that good, and the H/SC53 is very bad (it’s an AA light though, it’s bound to be less efficient), the SC700 is excellent.
I have a H600II and a H600 IV opened so I’ll try to measure those too.
The Skilhunt H04/H03 is often recommended as a higher value headlamp compared to stuff from Sofirn for example, thanks to it’s buck driver, but while it’s better than FET direct drive and to a lesser extent linear driver, its efficiency is not good for a buck driver.
The Convoy XHP35 driver has been measured here : Convoy XHP35 Driver Analysis / Testing / Schematic
(Modified to 6V and RPP FET bypassed so slightly better numbers than stock). And it’s very good, most of their switching driver looks to be using good synchronous converters and good components (low RDson RPP FET, decently sized inductor) so it looks to me that their offering are pretty good.