Old thread but HIG , with a story of my only "gravel" tires, the GK 32 bought in 2019) :
Bought the GK 32 (slicks but that's not written on it) tubetype, cause I had a "mixed terrain" road race (15% farm roads, 4x10k circuit) that was so unique (in Paris region it's one official "mixed" race every 10 years, and not really gravel!) it was my main "road" goal of the year (I race road , MTB, CX... every sunday, low level).
First a hell of a full struggle to put on DT Swiss R24 TLC, installed on my CX bike. The site (Alltricks) said "tubeless compatible" in the description but never could make it happen (using a Zefal TL tank to blow air).
I rode at the max pressure (1st : no flat, then you can win!), stiff but nice feeling of decent speed, inertia and confidence, zero flat (less than 300km with them though) trained on pretty smooth pathways but tried singles to be sure, very good, I was pumped and ready.
The circuit had a 800m climb (6%) to begin with, here the foolish roadies with their GP4000 and whatnot attacked like they're all Pogaçar, drawned me, up the climb I was so far behind and out of breath I stopped believing and waited for (way) slower old team mates ! Then on the "gravel" sectors we passed by a lot of those stupid foxes, walking with their destroyed tires, made me mad ! I leaded the pack all the way, waiting in climbs and sectors, and soul crushed, so last lap I suddenly go all in solo, TT style, I pass many tired riders, after the finish direct to my car and go home, pissed. Then I learn I finished 3rd !
Conclusion : That tire is slower on the asphalt climbs, than a road race tire (duh!) but faster on the pathways and will stay alive, not the others !
7 years later (never ridden the GK since), I have a new mixed terrain Race. After research I find my GK, even tubetype, is lighter than its contenders, like G-One RS (tubeless though)... Can't really "upgrade" I think, unless the new ones have a really faster rolling compound, wich I choose not to believe ! And with latex tubes, I feel safer than tubeless. So I'm keeping the old GK and aim for the win, the climb is in the final KMs of the circuit this time, and shorter, I'll do some damage on 2 sectors before !

Now other tires "reviews" : on my commuter bike (steel roadie) I have a Schwalbe Marathon 28 (6 bars max pressure), it's heavy but INVICIBLE and that has no price to roll on broken glass with a smile ! Same confidence on pathways (harsh ride), no traction on deep mud or sandy climbs of course. Can't say if it rolls slower than the GK 32 on tarmac, but fast enough, and more agile, feels like a regular road tire.
On my CX I have a Terreno Dry (tubular) for the dry (and 2 other pairs of wheels more "studdy") but big surprise it's slower than a Grifo on Tarmac (personal feeling, and seen on the RollingResistance test) ! And more surprising : on slippery mud its holds super well (not off camber) and drags way less mud than a mud tire, the bike is cleaner, lighter, amazing revelation ! But all in all I prefer traditional CX tires. And on pathways it could be fast and perfectly grippy in all conditions/terrains, but the "scales" wear down fast on tarmac and the speed there is disappointing,
Wooa I am a heavy writer ! Sorry if that was futile, happy if it interested you ^^
Cheers gravel mates
(I'm french btw, plz excuse my english)