Most fans wondered how he'd fare at a bigger club and bigger transfer budget so it has to be acknowledged that PSG was a failure.  Not least of which because his combative style approach to coaching saw him unable to control a dressing room of bigger personalities.  It worked at Sevilla & Valencia but not without breeding contempt among young talent (Isco & Deulofeu).
Arsenal could be a great fit IMO as the biggest issue the Gunners lack is the sort of resolve to deliver consistently - meaning Wilshere, Bellerin et al will no longer be able to coast as the board is likely to give Unai time to implement his approach.  I believe as nutty as Gooners are, they will ultimately be pleased with Emery