I had a 2006 Burgman 650 Executive, from a period when I was a bit heavier, had back issues, and wanted to try something different. It was what I moved to after I sold the BMW...quite a jump, what?
I bought mine with 8000 miles on it, and sold it three years later with 24,000 miles. I had NO problems with it. Except, that doing work on the engine was quite a challenge.
Now, a few things to keep in mind: First, a B650 is not a scooter the way most of the others are. That two-cylinder engine is frame mounted. That's good, in terms of ride and handling. But the power transmission gets complex.
I had no issues with the transmission - a sort of CVT with various steps, to simulate a conventional gearbox. But there's a piece in there, called a "stopper bolt" - that catches the movement of the variable pulley - and on earlier machines, it had a way of failing. And once it did, repair to the CVT was more than the value of the bike. Basically, the machine was totalled.
Suzuki put out a replacement bolt that is not prone to failing, but they never issued a recall. The improvement was done on the line, about this time, 2011. You could ask the dealer or a Suzuki mechanic about it. Removing an intact bolt and putting the improved part, is not such a crushing job.
Other than that...the only downside I had, was the seat. First, it isn't designed for tall Americans. I had to modify it (remove the butt-stop) to make it comfortable. I had a backrest someone made me, out of an Isuzu car headrest.
Second, you're sitting ON that seat, not straddling it as you would a bike. The way the B650 is set up, you have clearance to lean into turns. But you don't have the ability to clench the gas tank or frame with your legs. Grab the bars and hope you don't slide off and out.
Otherwise, a fine machine. Silky smooth engine. Fuel economy...not that great, about 45-55. But it was a great touring machine...I took mine from Wisconsin, where I lived at the time, to Seattle and Crater Lake in Oregon, and back. The windshield and fairing kept me dry in rainy weather.