I have had no problems whatever with the S50 in 13,000+ miles.
New tires at 10,000 miles, but they would have gone another 2K if I had pushed them. Better safe than sorry (BSTS).
Replace the battery after 3 years. Had no problems it, but then again BSTS.
I think the Suzuki S50 is one of the best bikes I have owned. The closest bike I have owned to the S50 was a 1978 Yamaha XS750.
I started in 1964 on BSA 650 Lightnings and the S50 is my 21st bike. It is by far the most reliable of all the bikes.
The valves were adjusted at the 1st recommended service period, and all oil, coolant and filter changes followed as per the manual.
I found the stock seat a little firm for my 65 year old behind on long trips (200 miles +) and bought a gel seat replacement. I have a fairing type windshield, and take 400 mile round trips on weekends with little discomfort. The footpegs are more under the rider than most cruisers, and that keeps my old back straighter.
My S50 is not as cold natured as some are reporting. I use the choke on cold days for the first mile or two; after that it is OK.
I like the low / no maintenance of the drive shaft.
The S50 is not the best handling bike I have owned, a little top heavy around town, but steady as a rock on the highway. I realize that the fork angle has a lot to do with that. But then it is not meant to be a sports bike.
The acceleration is fantastic for the displacement. My neighbor with a 96 cubic inch Harley and I ride together often, he tried to out accelerate me a couple of weeks ago and could not do it. Of course his bike weighs 750 lbs compared to 443 for the S50. It cruises easily at 80mph and can accelerate for passing to well over 100mph. Top speed I haven’t explored, but it was still accelerating at 105.
I get 50 to 55 mpg around town and highway combined if I don’t get on the throttle, 55 on highway trips. It drops to about 45 mpg if I full throttle accelerate in town.
I have had no problems with the chrome on the exhaust that some are reporting, and no finish problems elsewhere.