I’ll say the same as always. If you aren’t electric inclined. Do Not get an automatic transfer switch. They will fail. Get the generator and a double throw switch. You won’t regret it
We installed a generator at the farm so that my elderly mother could remain at home. They have lost power for as long as a week due to ice storms. For her use, it had to have a transfer switch. She went a couple years without it ever coming on. Now I'm told power has gone out 3 or 4 times in past month......and it has fired up and ran each time.
Downside to the transfer switch is if the power just flickers........our unit will fire and run. It has to go thru the entire startup process, runs diagnostics, then runs for several minutes after it detects the line power has returned.........then goes thru the power down cycle to hand power back to the line source. What would be better for her is if it had a timer........say power off for 10 minutes or so.......before it would fire and run. She isn't up to it, but if that were me, I'd use the manual transfer. When power goes out.......the great unknown is if it will be out for seconds, minutes, hours or day. Depending on conditions outside, one can make the call as to flipping the switch. If winter or major storm and they don't know how long power will be out, time to flip the switch.
What was important to us was not enough to power up the entire house.......it was to run refrigerators and freezers........the fan and electronics on an LP forced air furnace, lights, etc. Hers is a 13kw unit and is plenty for her use. Critical that these have their own dedicaated fuel source. Propane that does not go bad and still works in winter.