Most people, myself included, had them figured as a close to .500 team this year give or take a few games. Maybe an 85 win team. But they do indeed have some chemistry, which is impossible to predict, and the manager and coaching staff have clicked. Enough good things have happened to overcome the adversity (injuries to 2 closers). The lineup by and large has remained healthy, and some players are having surprisingly good seasons (Nava, Carp, Drew 2nd half). Gomes and Napoli have had big hits--in fact you go down the lineup and everybody seems to have gotten big hits. Plus the pitching has been steady--Nieves and Farrell deserve credit for that. Cherington deserves credit for the FAs (minus Dempster--they'd like to have that $26 mil back). There have been good trades and bad trades. They got stiffed on the two closer deals, but struck gold signing Uehara. Peavy is helping them right now.
Just keep in mind this isn't the As or the Pirates. This is a $170 mil team spent to the hilt. They are doing what they are paid to do. But still they have struck gold on team chemistry--on the field. You can't predict that, but once you get it, don't be tempted to change it.