Suhitharan T, Teoh WH. Saudi J Anaesth. 2013 Oct;7(4):436-41
Ransomised control trial comparing LMA Supreme with i-gel in 70 patients, with leak pressure, insertion success rates and leak fractions among the outcomes measured. While no post-operative complications were reported with i-gel, three patients suffered mild sore throat and one had mucosal injury in the Supreme group. i-gel had a higher but 'clinically inconsequential' leak fraction.
Link to abstract