will get you pointed in the right direction. Per your post you are considering between 4000 - 7500 watts. That's a very wide range with significant pricing differences.
The key thing with regard to you question (I wrestled with the same things) is coming to terms with how much you wish to spend on something you hope to not need. Economics carried the day for us, so we went the less costly route though the inverter approach was certainly appealing on many levels.
In your case, with GenerLink, you can keep your costs to below $1,000 if you size smartly and buy prudently. FWIW we bought our Generac on Amazon, with free delivery. Hard to beat that.
Also, if you are considering propane-fired units, be sure to check the run times. When researching them I was surprised to see how VERY short many of the run times were when using a standard 20 lb tank - some only 4 to 5 hours. Not good.
Lastly - be careful when looking at "power ratings", as the approaches used across manufacturers are not standardized and some may be misleading. For example, many marketers of generators label their units based on max (surge) output - but the true running load is only 80% of that total. So one rated at 6,250 watts (surge) in reality covers you for only 5,000 watts (and that would be full load all the time). Conversely, Generac, for one, lists its units at the full load running wattage and not at the startup/surge wattage. In this example, their generator rated at 6500 watts can handle 8125 surge. Truth in advertising there, IMHO.
As you said, you may only use this a couple of times a year. To me that makes it hard to put a lot of money/technology toward solving a problem that may never come.