I like something that will "dig" in out back, I tend to be a masher and "power" my way over things and up climbs. The Conti and Ignitor work well for me without a big rolling resistance or weight penalty, but still get the traction I need for my riding style. The Ignitor on the front I always felt I was "chasing" the front, felt like I could do better. It wasn't terrible, but always felt lacking when pushing hard and having the tire on edge. The Aspen doesn't feel like that, it feels as good or better than the 2.35 Ignitor I tried without the weight or rolling resistance penalty.
Everyone has to find what works for them, but don't give up on the tubeless thing. We are big dudes and light stuff doesn't usually do well for us. Light is nice, broke sucks.