My 2d would be to say I've been using a Honda EU22i with LPG conversion all winter, about 300 hours of use, and it has operated flawlessly. My charger requires 70A and has worked fine. Simple to maintain and very quiet, especially if you point the exhaust away from the boat and any neighbours. I've had no complaints about noise, but plenty of folks enquiring about the LPG conversion. LPG burns cleaner and sidesteps the issues of needing compliant storage for petrol (which also has a shelf life and is more of a faff to acquire on the canals). You turn it off by turning the gas off, so any left in the generator is used up. I get an average of 35 hours out of a 13kg cylinder, so it's about 75p-£1/hour depending on where you get your LPG.
Two other issues to be aware of... boy dogs seem irresistably drawn to piddle on generators... and the EU22i cannot be run in wet conditions.
As others have mentioned if you just want power in the summer then spending the same amount of money (or less) on an oversized solar array will give you more power than you could ever want. Solar is also much better and obviously cheaper for maintaining LA batteries.