"reputation" and "league table rankings" will not necessarily tell you much about the actual delivery of the course, and within the engineering sector are irrelevant to recruiters. I would suggest you look at the course structure/content of each course, and also see what current and former students from each university have said in the past. In terms of employability I imagine they'll be broadly similar, provided you undertake appropriate work experience/internships/placements while on the course.
I would note UCL's engineering department has had at least in the past a persistently low student satisfaction ratings and current/ex-students from that department have on numerous occasions made threads complaining about the department. Some of these complaints (which would probably be reflected in the student satisfaction results) however may stem from unrealistic expectations of the nature of university study anywhere (e.g. lecturers generally not being that invested in students, focused more on their research, academics slow to respond to emails etc; such things are endemic in higher education and not localised to UCL engineering or anywhere for that matter)