i had offers from kcl, edinburgh and strathclyde as well as other unis outside the uk - i chose warwick mainly for my course which they don't do anywhere else + i really liked the campus when i visited! i'd assume one of the biggest differences is ucl being a city uni vs warwick being a campus uni so i'd probably consider what kind of location you'd prefer!
tbh I was mostly only involved with the more academic/career societies but i enjoyed events and projects with enactus, econ soc, women in econ, tedxwarwick, and wbs society!