There are a number of relevant indices, I've put a link to one below [1]. the short version is that they would probably be categorized as a multi-strategy event-driven manager, and as such would be compared against other similar managers investing in similar strategies (distressed debt, activist, etc). Most hedge fund managers are focused on risk-adjusted returns rather than relative returns and people often use either a sharpe ratio [2] or sortino ratio [3] as a rough proxy in addition to measuring pure absolute returns.
[1] https://www.hedgefundresearch.com/family-indices/hfri [2] http://www.morningstar.com/InvGlossary/sharpe_ratio.aspx [3] http://www.morningstar.com/InvGlossary/sortino_ratio_definit...