HS might be hyper-sync, which is to my mind NOT the same thing as High-Speed Synch...the folks at Pocket Wizard inented hyper-sync a few years back, and that was a time-offset system that allowed "a little bit faster" synch speed, like say 1/400 second instead of 1/200 or 1/250 second, while High-speed Synch is like FAST speeds, like 1/500,1/800,1/1000, and even alllll the way up to 1/8000 second, so it is absolutely necessary to KNOW, for sure, what they mean by "HS" if you want to be able to use true, high-speed sync at fast shiutter speeds like 1/4000 or 1/1250 second,etc.
I do not think that TTL flash control is all that valuable for monolight units! I have never used TTL flash control on anything except a camera-connected speedlight sized flash; for decades, powerful flash units have been used without TTL control, and as far as I kjnow, the Profoto B1 was the **first-ever** monolight-powered battery-powered flash that offered TL exposure control.
Again: I do NOT consider TTL flash control to be "a good thing". WHy would I ever weant the flash unit to determine MY exposure? Isn;t that something that **I want to control*** for myself? I think it is
For the money spent, the Xplor 600 looks like the best "value": It is currently $749 per unit!!! Spending $2,300 or more for ONE FLASH unit is....dumb, at this level....if you were earning $60,000 a year off of outdoor flash work, it would be different!
Flashpoint XPLOR 600
The Explor600 is both HSS and TTL-capable!
Flashpoint/Godox XPLOR 600 HSS TTL | Full Review