055 much more substantial. More stable, especially extended. Heavy camera combo, go for the 055.
Get the pro version, as the versatile column could be handy for the little premium.
When you get it, unscrew, grease and tighten all the clamps. I had a 055XDB fail on me last year, just out the box. Clamp wasn't assembled properly so worth checking, to be fair I have and have used loads of manfrotto gear over the years and this was my first problem.
I hate b&s heads (except the mircoball) I find the 3 way heads much more useful, and easier to adjust.
I have the 498 RC on a table top dolly, very solid, but I just find them cumbersome to use, generic to their type.
As I recall from when I was buying the main difference between the 496 and 498 was the panoramic etchings around the base of the 498.
If you want a rapid adjust head I would look at a pistol grip type instead, but thats just my preference.