Great thread timing as I am looking for tires for my 550 too.
I used the Roadriders on my last two bikes, the Royal Enfield 500 and the FJ1200, and liked them alot, especially on my Enfield, which was closer in size to the 550 than the FJ.
The Enfield had vintage Dunlop style tires on it (ribbed front, flat blocky rear) when I bought it from my dad. The Roadriders have a more rounded, sport-touring shape, handling was vastly improved as the bike easily flicked from side to side and interestingly the overall ride improved too.
They seemed to be durable too. I put about 5k on the ones on the FJ (a 600 pound bike with a 220 lb rider) and they were in great shape when I sold it without much visible wear.
I will say that they didn't feel quite as secure though on the FJ. My confidence level in the twisties was only so-so, but then again I didn't really have prior experience with a large powerful bike like the FJ before I bought it, so it could just have been me.