GSXR600 1999 or ZX6R J2 2001

Please can any one help me I'm looking to change my bike for one of the

GSXR600 1999 or ZX6R J2 2001

And would appreciate any advice on what to look for in the way of defects
that may plague these particular models i.e. I have read that there are
problems with the GSXR cam chain tensioner on early models (anyone know if
it was fixed in this later model). Also apparently the GSXR likes to eat
tyres, anyone had experience of this and found a tyre combination that lasts
longer than the 1200 miles rear, 2500 miles front (MCN magazine) etc.

Tires getting used up is dependant on tire compound & riding style. I buy new
tires each year becuase I go with very sticky tires.

The cam chain tension is almost a non issue -- most of us have swtiched to the
manual tensioner; which is an easy and inexpensive change.

I prefer the gixxer -- but the ninja is nice too; and each year; makers keep
improving.