Which porting studio made the most impressive Switch ports?

[Leynos]

If by impressive just most demanding game then yeah Panic Button. Impressive how accurate the game is to its original hardware with the least input delay or issues for older games. M2 as always. City Connection has had trouble with input lag in their Saturn tributes. Maybe because they are using an actual Saturn EMU on Switch. Dunno.  M2's work knows no equal for older titles.