Fun Weiss stats. Taken from 2011-2012.
Was on the ice for more 5 on 4 PPG (for) than Stamkos.
Was similar to guys like Bergeron and Duchene for PPP/60 min. (That's roughly 50th amongst centers in the league.) It should be noted that Weiss was a fair bit higher than Fil, even though this was Fil's big year. Filppula ranked in at 72nd place.
1.17 first assists per 60 min of PP time. That was better than Kopitar, Richards, Spezza, etc. 1.64 secondary assists, which was on the level with Stastny and Hudler, and better than Eric Staal. PPG/60 was also 1.17, which was just a hair behind Hossa, the same as Lecavalier, and better than Eric Staal.
Behindthenet doesn't seem to track 5 on 3 data.
Bonus fun: in 2009-2010, Weiss put up 4.64 points per 60 min of PP time. That was more than Zetterberg, and Crosby was at 4.8 and Datsyuk 5.38. Weiss had 2.52 PPG per 60 min of PP time that year, which was higher than Ovechkin, Vanek, Malkin, Datsyuk, Crosby, etc.
In 2008-2009, it was 4.27 PPP/60. That was better than Kovalchuk, Heatley, Henrik Sedin. Scored at the same PPG/60 rate as Crosby. More secondary assists on the PP per 60 than Datsyuk.
Again, that's all at 5 on 4. But my general point is, Weiss has been a very valuable power play guy at 5 on 4 throughout his career so far, especially if you take into account that he's never had fantastic offensive talent to work with.