The best one is the one that can run flawlessly after sitting in your garage for 3 years doing nothing…. I recently bought Firman Tri-Fuel from Amazon because it was damn good deal and tried it on Propane and Gasoline. The unit started right out of box on propane (less than 5 seconds) before failing after about 40–50 seconds of operation. Went though support and the verdict was that the unit was faulty (Voltage regulator was bypassed as per their instruction which apparently a common issue for these units). Then I tried it on gas and it did not start… Good thing I tried it before winter comes. I returned it back to Costco.
Then I spent hell of the time researching for the best out of best and here is my subjective findings:
Most of the Firmas, Champions, Cummis, Westinghouse, etc. are essentially same units and/or sharing the same components made on the same factories in Asia. If you look at their same size kW models you will see that there is a lot in common (specifically motors and generator itself). Many of them offer dual and tri-fuel options which is very convenient.
The units that stay apart from the commodity brands are Honda, Yamaha and Kohler. CAT just left the small genset business what I understood.
Honda is claimed to be reliable and quiet, has its own engineering and not sharing anything in common with the commodity brands (at least I could not find anything).
Yamaha is claimed to be reliable and quiet as well - has its own engineering and the best - they carry their own electronics/controls (Yamaha is good in electronics).
Kohler is another brand on its own but I did not look deep in their portable units. I use a lot of the Kohler units on my commercial projects and they are quite reliable but it does not mean it would be the same for the portable sector.
My choice was Yamaha EF7200DF which is considered a working horse for the contractors. It has brushless alternator and very high reviews. It is a single-fuel but there are tri-fuel kits that you can install on it. It will cost me extra $200USD plus shipping to Canada. The kit manufacturer claims that there is nearly no brain installation and change to the unit (it is literally addon to the unit’s carburetor). Honda was no go option for me because of my bad experience with their motors. I don’t like their engineering and in fact the last drop was my Honda mover that failed after 4 years of operations on the best gas and maintenance. I repaired the problem but was shocked to discover the problem - which was a $20 CAD part. If I had to service it somewhere - I would pay at least $200 CAD. In addition to that I believe that Honda is overpricing its units big time.
As far as inverter vs generator: most of your household equipment can easily withstand 20% total harmonic distortion and any generator even the cheap one will stay at that level. The inverter gives you the pure sine wave but do you really need it? If most of your household equipment can either tolerate the THD or rectifies the sine way into the DC and barely feels the power distortion - why paying extra 40% more for the inverter? Yes, inverters run more efficiently but are you really concerned over the efficiency during emergency situation?
Again, anything I said is very subjective based on my personal experience.
10 Best Portable Generators
Based on dozens of customer reviews and ratings, the followings are the top 10 best-selling Portable Generators: