year 2 winter boutique m&a (three months experience already but can extend) / big four assurance ?
depends on what you are aiming for in penultimate/final year I think
m&a in a boutique is much better if you are aiming for IBD/consulting in the future
but big 4 audit is also a good stepping stone for different roles given the brand name
seems boutique M&A is sexier than big4 assurance, and you still can earn back the big4 offer in later stage....