I just had a game where my opponent and I were constantly destroying each other's lands with Strip Mine in the early rounds. An Eldrazi Temple into It That Heralds the End, answered with Force of Will - I simply didn't have any lands in play. Luckily, a Flood came along, and I was able to establish a small board - Tamiyo and Orcish Bowmaster, then a Psychic Frog. Next turn, I could transform Tamiyo. My opponent bricked, a quick GG, and conceded.
Timeless is incredibly fast and incredibly ruthless. Thoughtseize, Force of Will, permanent self-burn with shock and fetch lands - no format in Arena embodies "life is only a resource" more than Timeless. Anything goes here - land destruction? Of course! Free counterspells? Absolutely! Aggressive hand disruption? Naturally!
The rounds are fast, every decision carries weight, the combos come quickly, and they are all devastating. I haven't had this much fun in a long time, and the people in the queue are so refreshingly non-toxic. So far, I've encountered virtually no one spamming "Oops!" or abusing the timer.
Timeless is by far the best Magic Arena experience I've had. I highly recommend it!