Let's break it down here.
Centro has clearly already had the better career. He's got a couple outdoor world championship medals, and an indoor gold (for what that's worth). He's also got a very good 1500 PR.
Webb is better in every other way, that is to say, Webb is by far the superior runner. He only had three healthy season's as a pro, which means Centro's pro career has already been much longer than Webb's. Webb was just starting to hit peak years when injuries sapped him over those long post-2007 years. Webb had massive talent and massive range. Based on his times he could compete globally in any event from 800 to 10k. He's got the AR in the mile. He's got a DL win and several other big international wins. In the three healthy seasons he had he dominated the US championships every year. Every time he stepped on the track he was a favorite to win, and often he was dominant. Oh and not to mention he was the best middle distance runner in the world in 2007 - fastest 1500, fastest mile, 2nd fastest 800, and absolutely destroyed any challenges in the final 100 that year, seriously insane kick. He also inspired a generation of runners and single handedly put America back on the map in the distance running world.
If you ask me which career I'd rather have I'd say Centro because Webb's career was brought down by injuries so early, he should had probably 10 more years of good international level running in him.
But if you ask me who the BETTER, more dominant, more talented, more inspiring, more memorable runner is, well that is Webb by a mile.