If you have origional(or heavily worn aftermarket ones), mabey a set of shorter shocks would work, and give you better shocks in the process.
Personally, I do not like the thought of lowering blocks as it tends to offset the position the shocks mount on the rear swingarm.
It probably doesn't make that much difference in handling, or reliability.(dunno, never tried them)
Shock lowering blocks just seem the cheap/easy way to acheiving what a new 1" or 2" shorter set of shocks will give you.
just my .02....
l8r