This Westinghouse generator is a fine example of how a back-up generator should be designed and built. My use is for a whole house back-up generator that will be semi-permanently installed, ready to go at any time (still doing the install). On gasoline, the generator is rated to start heavy loads of up to 12,500 total Watts (52 Amps at 240 Volts). Or, with just over 100 Amps of 120 Volt starting power available, it can start a collection of 120 Volt devices with motors that can take a little extra time to start under load, such as refrigerators, freezers, air conditioners, compressors, etc. This generator has serious creds and can start/run most household combinations of 120V and 240 V loads. This well-made beauty will last for a very long time.In my opinion, the main reason for its conspicuous strong performance is that Westinghouse has designed-in a very strong 18 HP, 457 CC engine which can readily power typical loads that, on startup, exceeds the continuous rating of 9,500/8,500 Watts (gasoline/propane). A great many generator engines will run out of horsepower during electric motor starts, but not the Wgen9500DF.I've not yet tested the generator with propane because my propane plumbing is not yet complete, but with gasoline the engine has been an exceptionally strong performer. Other reviewers of this genset have expressed no problem with propane, so I expect the same. Compared to my earlier unfortunate choice of a Genmax 7250/6000 Watt (starting/running) with appropriate loads, the Westinghouse 9500DF is far ahead in all aspects, from capability to quality. One obvious example of a significant difference is that the 9500DF is rated to deliver full output at up to 5000 ft of elevation without carb adjustments, which should make it an absolute beast of a generator for starting and running max loads in the areas around sea level. An available high- altitude carb kit enables operation above 5000 ft. Compared with the Wgen9500, the Genmax can deliver its specified output power only when below 2000 ft. A "high altitude" kit is required for anything between 2000 ft. and 4800 feet, it's max altitude. I'm at 4000 ft where the 9500DF has significant reserve horsepower and readily starts and runs heavy loads well within its specifications.The quality of Westinghouse generators is well known and thus are recommended by respected consumer organizations. It only helps that I can easily start the 9500DF at all temps between 24 deg F and 89 deg F, and the remote-start fob works 200+ feet away with a good battery installed.The WGen9500DF dual fuel generator is very unlikely to disappoint, especially with respect to the warranty. The Genmax warranty is only for "substantial defects", and they decide what that means. They require that the purchaser pre-pay round-trip shipping of any generator with a problem to their single US repair location for evaluation and possible warranty repair. My Genmax had a dead display out of the box, but the warranty requires that pre-paid shipping before they would inspect and consider whether or not to repair under warranty. Several phone messages were left at their repair center, but no call-back. Later, after I'd already returned the new Genmax (thank you, Amazon!) and had purchased a Westinghouse generator thru Amazon, Genmax finally called and eventually said that they would provide a free replacement display to me if I would fix the brand-new generator myself. No, thanks. The Westinghouse warranty is simple: If the customer provides for reasonable care and use, parts and labor are fully covered for 1 year, and parts-only for 3 years. There are many, many authorized repair stations, so shipping is typically not required.The only thing that bothered me a little, and this is picky, was that the 9500DF user manual had some mistakes. Someone must have converted another manual and missed 3 or 4 items, such as that, on the cover, the genset is said to be a Digital Inverter Generator (I wish), that it has an ECON switch (nice, if it was true), and a couple other nits. When mentioned to customer service, they thanked me and told me that a revised manual was already in the works. All's well that ends well.If you get one of these fine gensets from Westinghouse, you'll not be disappointed. Westinghouse and Honda set the standard for top-quality generators, but Westinghouse wins the price/value comparisons.