I put in two full rounds with the Sarek, replacing my Gold Line Pure.
Early thoughts: It was very slick new which reduces the trust factor in grip and rip. As the rounds went on and I had to clean it up a few times, this disappeared as I expected. Lesson is, and this applies to the second one which I did not throw, give it a bath before you play.
As a driving putter: It is a touch more high speed stable than the Opto Pure and a little slower than the Gold Line Pure. It holds the line (flat, hyzer, or anhyzer) even at power and for the most part finishes flat when thrown flat. It likely will not accomplish anything you have not seen before. It does not seem any shorter or longer than expected. It reminds me a lot of a good Ion, which I guess is what is to be expected.
As an approach putter: Here I do not like it as much. It gets the job done, but some times it is difficult to judge how much power you are going to need. Most of the time I was over-shooting the intended landed spot. Here it reminded me a lot of the Warden where you get enough height to run at the basket, give it enough power so that it does not come up short or fade out early, and you will likely find yourself on the back side of the basket just out of putting reach.
As a putter: Here I could not dial it in at all. I was completely all over the place with zero confidence. I am far from a world class putter, probably in the lower half of the field, qualifying easily for the world's worst putter, but I had zero confidence with it. Once I was outside of 35 feet, it was impossible for me to run the basket. Maybe something with how it feels in the hand or some other convenient excuse, but I found myself putting nose up, which lead it to sailing over the basket. HOWEVER, once I was forced into a straddle putt, I dialed it in almost instantly. I grip the disc a little different and obviously I have a slightly different release trajectory from a straddle. It worked almost flawlessly.
I might keep one in each of my main two bags, but until they become more widely available, it might not be anything more than a curiosity to throw on fun rounds. It does not accomplish anything more than what I was already getting down with my Gold Line Pures. Still, if I were to get my hands on 1-3 more of them, I would be inclined to place them in my bag as a driving or straddle putter.