[jonathankoren]

Yes. Some mods like kerbal engineer and machine everywhere makes thing less annoying, not easier. It’s the engines, fuel tanks, and science payloads that can break the balance.

As for mechjeb in particular, I never found it all that useful except when calculating rendezvous. I could do it myself, but I don’t want to bother with a protractor and calculator.

[DuskStar]

Mechjeb is also invaluable when doing preprogrammed burns on remote probes with a high light lag like you'll see in Realism Overhaul.

Timing a 30s burn when the probe takes 15m to get the signal is rather irritating.