The rankings are unlikely to make much difference to future job prospects and they fluctuate a lot, so don't pay too much attention to the rankings.
Go for Cambridge if you want a broad-based engineering course which is heavily science-based and you specialise later. Go for Imperial if you just want to focus on a single engineering discipline from the start. I hear Imperial is also quite science-based but not as much as Cambridge.
Are you 100% sure you want to do EEE? Lots of Cambridge engineering students switch their specialism in the first or second year.
And if you want more time to decide you could always apply to both and decide later...