Since this question was posted, there have been many more studies in the literature about the effects of DST. Here I just summarize the first 13 papers (some are gated) that show up on Google Scholar ("Daylight Saving Time", with filter 'since 2010')
My tl;dr conclusion: Most but not all say DST is bad.
(1) uses a natural experiment in Indiana:
DST saves on electricity used for illumination but increases electricity used for heating and cooling. ... the latter effect is larger ... DST costs Indiana households an average of $3.29 per year in increased electricity bills, which aggregates to approximately $9 million for the entire state. Finally, the social costs in terms of increased pollution emissions range between $1.7 and $5.5 million per year.
(11) finds that in India (which does not currently have DST) will benefit more by advancing the current Indian Standard Time by half an hour, than by adopting DST.
(12) finds that DST reduces electricity consumption by at least 1.0% in both Norway and Sweden.
(2) looks at data from Swedish Heart Intensive Care Admission and finds
an elevated incidence ratio of 1.039 [for Acute Myocardial Infarction] for the first week after the spring clock shift forward.
(3) finds "a dramatic increase in cyberloafing behavior".
(4)'s abstract states very tentatively that
Indirect evidence of an increase in traffic accident rates, and change in health and regulatory behaviours which may be related to sleep disruption suggest that adjustment to daylight saving time is neither immediate nor without consequence.
(5)'s abstract suggests that sleep-adjustment difficulties is severest for those who habitually sleep less than 7.5 hours.
(6) looks at Finnish data and concludes: "It seems that sleep deprivation after DST transition is not harmful enough to impact on occupational accident rates." (10) is by some of the same authors and has a similar conclusion.
(8) finds a "rise in Road Traffic Collision related injury figures up to two weeks following the spring time transition." (9) seems to be just an updated version of (8) with the same conclusion.
(13) finds that DST lowers SAT scores.
(7) states there is an "economically large negative daylight-saving effect in U.S. stock returns".
Sources (Journal publication date in parentheses)
(1) Does Daylight Saving Time Save Energy? Evidence from a Natural Experiment in Indiana (Nov 2011)
(2) Daylight saving time shifts and incidence of acute myocardial infarction – Swedish Register of Information and Knowledge About Swedish Heart Intensive Care Admissions (RIKS-HIA) (Mar 2012)
(3) Lost sleep and cyberloafing: Evidence from the laboratory and a daylight saving time quasi-experiment. (Sep 2012)
(4) The impact of daylight saving time on sleep and related behaviours (Aug 2013)
(5) Individual response to the end of Daylight Saving Time is largely dependent on habitual sleep duration (2013)
(6) Work-related accidents and daylight saving time in Finland (Nov 2010)
(7) EFFECTS OF DAYLIGHT-SAVING TIME CHANGES ON STOCK MARKET RETURNS AND STOCK MARKET VOLATILITY (Feb 2013)
(8) DAYLIGHT SAVINGS TIME (DST) TRANSITION: THE EFFECT ON SERIOUS OR FATAL ROAD TRAFFIC COLLISION RELATED INJURIES (2011)
(9) THE EFFECTS OF DAYLIGHT SAVING TIME (DST) TRANSITION ON SERIOUS OR FATAL ROAD TRAFFIC INJURIES IN GREAT BRITAIN: AN ANALYSIS OF TWO INDEPENDENT NATIONAL DATASETS
(10) Daylight Saving Time Transitions and Road Traffic Accidents (2010)
(11) Year-round daylight saving time will save more energy in India than
corresponding DST or time zones (March 2012)
(12) The impact of daylight saving time on electricity consumption: Evidence from southern Norway and Sweden (June 2011)
(13) Detrimental effects of daylight-saving time on SAT scores (Feb 2011)