Differenc of opinion. :>) I think Kaley Cuoco is better than Alyson Hannigan. I especially liked Kaley in the first season of 8 Simple Rules for Dating My Teenage Daughter. She was a wonderful foil for John Ritter.
Well, guess it’s a matter of taste. I find Alyson’s humor to be deeper and subtler. Perhaps from being in the biz longer and having worked in drama (Buffy is sort of a drama, yes?). If you can wring comedy out of something like Buffy, then How I Met Your Mother will be slumming (which to me Lily is doing). Kaley was marvelous in 8 Simple Rules, but it was harder to see because the whole cast was top-notch. When your mom is played by Katie Segal and your dad by John Ritter, the bar is set pretty high. But, she did stand tall and even wangled a few good narrative arcs.
Good on her. Just wish she could get better film roles.