Cubs can certainly be competitive within a five year window, but the way free agent contracts work is you overpay for the last few years to get some value in the first few. The value for the Cubs in this deal seems to be all before they will really be a contender. Don't really get it. That said I'd consider 5/75 a great deal for just about any other club.
Also, lol at all the people who want Porcello. He sucks.
Porcello is young, improving, one of the best GB starters around, and likely to be undervalued because his surface numbers are gross due to the Tigers' awful defense. Did anybody know he had a 3.91 FIP last year, good for a 2.9 fWAR? I was shocked when I found out. For 3 years in a row, his K/BB, ERA, FIP, and xFIP have all improved. He's only 25 next season, a former very top prospect, and last year saw his avg fastball velocity jump from ~90 to 92. He's never had injury problems and doesn't rely heavily on his breaking ball, or throw a cutter.
Advanced stats don't tell the story in Porcello's case. He's eminently hittable and the results have said as much for three straight years. He had a 2.9 fWAR last season compared to Jered Weaver's 3.0 and that's absolutely laughable.