Indeed, the interchanges can be quite arduous, as it tends to be very deep, and usually quite a trek from the other lines in that station. This also means it can take a good chunk of time to even get to or from the platform.

For example, if you wanted to go from Farringdon to Liverpool St, Google Maps would suggest using the Elizabeth line, but, in practice, it's usually better to use the sub-surface lines (Metropolitan etc). The time taken for the extra stops will be cancelled out because the Elizabeth line takes significantly longer to get into/out of of as it's so much deeper. Add another couple of minutes if you happen to get on the wrong end of the train, because those platforms are long!

That being said, it's a joy to ride and is the only air-conditioned train that runs through the central section of London.