I have a generac 18kw whole-house generator with an automatic transfer switch. Love it. Had it 7 months and it's been needed twice already. I would have no reservations about going with a Kohler too. They make really good generators, but I had fewer options for installers.

We lose power all the time and I didn't want to have to take manual intervention to get the generator going. The whole-house generator is a hands off solution. Never have to worry if I'm not home or don't have enough gas or whatever. Power goes out and it starts. If I lived in an area that didn't lose power a lot I probably would have done a 10kw portable that runs on propane or gas. Build a shed for it with the exhaust piped out and automatic fan venting. You can google it, lots of videos on that. It helps keep your generator safe from rain and helps cut down the noise. Total cost of that would have been maybe 3-4k...which is lots less than the whole house generac. With a 10kw portable you can usually run A/C, but you can't run everything at the same time. It's not that kind of power.

Had I gone with the portable, I would have had an electrician install the hookup and interlock kit. It's local code to have the interlock kit and there's really no chance that you are going to back feed when it's installed properly. It's not a good DIY project. Those linemen have a tough job, nobody should booger up a solution that puts them in jeopardy. You really don't need to worry about it if you have a pro install.