I bought one with the bike, and I love it. Easy chain maintenance, and a lot easier to take a wheel off if you ever get a flat tire.
The only disadvantage I've found is that a bottom small section of the bodywork (the "bellypan" I guess you'd call it), has to be removed for the center stand to fit.
As far as stability, just remember this:
With the center stand deployed, you have only the front tire contact patch plus the 2 contact patches on the center stand holding up the weight of the bike.
With the side stand deployed, you have BOTH tire contact patches plus the side stand contatc patch, and the total square inches of contact is therefor MUCH larger, so the pressure on the side stand patch is lower (i.e. the sidestand is less likely to sink into hot pavement than the center stand is).
In addition, if you take the time to ensure that (a) the bike's front end is either at least level to the rear end, or higher, and (b) the wind is not blowing from the rear of the bike to the front, and © the parking spot is either level or tilted TOWARD the left (rider) side of the bike, the side stand will provide more reliable protection against wind tipover.
Jim Gnitecki
JimGnitecki@msn.com