I previously worked as an assoc in Rx and spent some time as an analyst in M&A. The standards of each output differ by team (ppt, excel etc) however they are very high across the board, particularly in LDN. First 6 months are extremely hard however once you survive things become easier (not easy). You become a much better banker in an independent like Lazard vs BB and can exit easier IMO. Hours are tough (same as BB) but you have huge responsibility, if you want to become the best and learn the most and get strong exits, then I would recommend Lazard.