In reality, backfeeding the grid is not as big of an issue as the
power company makes it. Attempting to backfeed to your neighborhood
will usually stall your generator. Even if you do manage to
backfeed, you stand a good chance of frying your genset when the power
comes back on (fire/electrocution hazard). Linesmen take precautions
even if a line is supposed to be dead. But still, that very slim
chance of energizing lines and presenting a danger to lineworkers is a
concern. That concern is expressed in electrical codes as a
requirements to not install equipment that can backfeed.


All that said, I would still recommend a transfer switch for it's
simplicity



Definitly worth it, it only takes once of someone forgetting to kill the
main breaker, or forgetting to disconnect the generator before switching it
back on. Your generator will be running out of phase with the grid,
connecting it on accident can do very bad things.