[fasterblaster02]

As a former Generac installer/tech, I have a few thoughts. I would consider Generac to be at the bottom of the list for quality(with the caveat I have never touched a Briggs). I've installed and repaired quite a few of the units. The few Kohler units I worked on impressed me, and the few WinCo units impressed me even more, in comparison to the Generac units I was familiar with. Now, I haven't been in that business for about 3 years, so things
may have changed a bit.
As far as sizing, consult your installer and they should be able to get that right for you.

 

[fasterblaster02]

I'm curious now. Would you care to elaborate? What impressed you with the Kohlers and WinCo's more than the Generacs specifically? And since you've only been "out of the loop" for 3 years, I would consider your information to be relatively up to date.

The WinCo air-cooled units were powered by Honda or B&S Vanguard, which both are a definite upgrade over the Generac. They had a more no frills and simpler electronics setup, similar to the old square Generac units, which were of better quality than the new ones.
The Kohler units fell somewhere in between in my opinion. The case itself was possibly lower quality than the Generac, but otherwise seemed more well built.

With any of the brands, if you get cold temps where you live, I would highly recommend a cold weather kit. For a Generac, this consisted of an oil filter heater sleeve, and a heated battery pad. The other brands may have something similar, or the Generac kit could probably be adapted to work.

It has been a few years, so there may be some changes I'm not aware of. Most commonly replaced items on a Generac were: batteries/battery chargers, controllers, choke solenoids(the newer models had a completely different airbox design that was a big improvement). We had a run of generator stators for a while there, but Generac even replaced some of those out of warranty.