I love the metrics, because they do a lot of combining and give you a more clear picture. If you just look at steals you would say Chris Paul is a better defender, but if you go to the advanced metrics they take into consideration a wide variety of things to determine just how much of an impact someone makes on defense. I think steals is a very overrated stat. Allen Iverson was not a great overall defender, but he sure he get a couple steals every game. That's why when you look deeper it shows that Drose is probably a better defender, which makes sense because he is more athletic and has better measurables to matchup with other point guards.
I think PER, win shares, WAR, etc... are pure gold. Yes you can take an assist/TO ratio and gain value, but you can't always gauge it because of the players around you. TO% gives you a look at the true turnover rate without needing to look at the ability of other players around you to finish. Now when a guy like Steve Nash can get a ton of assists without a great supporting cast, now that's PG at it's finest and you don't have to look at the advanced metrics...however, to see his overall impact you do.
Now don't get me wrong, you can look at regular stats and they can be useful, I just don't think they do a good job at telling the entire story. In a time when so much is media driven and awards are won or lost based upon how many ESPN highlights you have, metrics are the way to go. Just ask Lebron James how he made the all defensive team...it's called the chase down block and it looks good until you get in the playoffs and get torched by Jason Terry. I'm not saying Lebron is not a capable defender, but ESPN drives his status to higher than it really is on that side of the ball.
I'm a baseball guy and to truly tell if a guy is good on defense you can't just look at errors and fielding percentage. I love the defensive handbook people come out with because it shows that guys like Derek Jeter are frauds defensively (no I'm not discrediting his offense or his leadership). Reading into things you will see that Jeter has terrible range as he has posted 2 of the all time worst single season put outs per nine innings numbers. On those teams his starting pitchers were only middle of the pack in strike outs so he had just as many opportunities as other players. Sure he could have had bad luck one year and be on this list, but to be consistently low on this stat is an indicator of range. That's also why he had to rely on a jump throw...his arm wasn't strong enough and he couldn't circle around a ball in the hole. Same reason why you don't see him dive to the hole and throw people out from his knees. The fact that he has a gold glove is because people try to only use the media and regular stats...not the in depth look at the true defensive worth. As a disclaimer I will say that Jeter deserves to be in the hall of fame even if he never won a gold glove so that you don't just think I'm hating on him.
Anyway, that's just a couple examples I could think of....but it is the reason why I don't just look at the normal stats.
As for who I would take...I would probably take Rose. Better defense, shooting will improve because of the type of mentality he has to put in the work, and he is younger/healthier. If I had scoring pieces in place and it was for only 1 year, I would take the more seasoned, pure PG in Paul.