I swap between the 45mm Riddler's and 38mm Paselas regularly and while the Riddler doesn't roll on pavement as well as a smooth tread tire, it provides a ton of confidence in really loose stuff. I've run them as low as 25lbs (with tubes!) without any pinch flats. With 210lbs combined bikerider weight and running a good mix of loose gravel and pavement I usually get 1500 miles on the rear tire and 2500 miles on the front. I think that's pretty good for a tire this supple.
Mounting them sucks so much. The bead profile is made for WTB TCS rims which have a more square bead profile and it takes a ton of work to get them to mount cleanly unless you prep your rim. You WILL get wobble if you don't seat the bead uniformly and it takes a lot of pressure and effort. I've only been able to get these to mount cleanly by using soapy water on the rim and that is a supply that you usually don't have on you when you're on the side of trail trying to fix a puncture. Running tubeless with a tire repair kit (Dynaplug) hopefully means you can avoid all this pain because it sucks finishing a ride with a lumpy tire.
I do a lot of miles on my 'cross bike on mixed rides in New England. I've ridden everything from single track to gravel races on these in the 37s - run tubeless - and I'm completely sold on the tread pattern. It's pretty amazing what I've gotten up on these....real slick rooty climbs, not a problem. And they roll on pavement much more nicely than other gravel type tires. They mounted up on Stan's rims without any problems at all.
The tires have a good profile and track well in a variety of conditions. However, they dont fit my Alex CXD6 rims. Both of my wheels have a nasty wobble at a range of pressures, and I couldnt keep riding on them. I have never had this in 4 decades of riding and probably hundreds of tires mounted.
The 45mm width provided excellent handling on a route with sections deep gravel and lots of rough rocks. Did not roll as past on pavement as the 35mm tires I used before. I would feel comfortable using these on most of the single track we have around here. If you ride roads that are smooth and hard packed, you could find a faster tire.