How good are Terrance Crawford and Sadam Ali?

Hi all, I'm new to this forum and basically new to the sport in general. I haven't watched boxing since the early 90's, and even then I was only a casual fan at best. A few months ago, out of nowhere, I decided to look up some of the fights I vaguely remember. This time something clicked, and I wanted more. So I went through my HBO on demand selection, and watched a few fights from the last year or two. They were all good, but the Terrance Crawford/ Yuri Gamboa fight was amazing. When Crawford turned the tide in that fight, I was absolutely hooked on the sport. I began looking for fights to look forward to, and the Kovalev/ Hopkins fight was coming up. That was a good fight, but I thought the Sadam Ali/ Luis Abregu fight was even more entertaining. Mostly because Ali seemed to be such a huge underdog, and because the crowd was so agitated early, but Ali just kept working his game plan and turned that fight into a pretty good one too. Now, I think I'm officially a Terrance Crawford and Sadam Ali fan. But given how little boxing I've watched, I don't know squat about who else is out there. Crawford seemed like a very talented fighter, and genuinely likable person, and Ali seemed like an easy underdog to root for, but for all I know they could both be bums that just fooled me into thinking they were really good. So my question for some people that know stuff is this... how good are these two fighters? Can I expect to see them keep winning, or is it not worth getting my hopes up?