>after 500 BASE-Jumps, I would rather take a
>solid 3 sec delay slider down, than a 4 sec
>slider up on anything less than 800'.

Generalized statements like this can be very dangerous if taken as an absolute rule.

There are many (i.e. more than 75) sub 800' objects in the world where it is much safer to take a 4 second delay slider up than a 3 second delay slider down. Depending on the shape of the object and the wind conditions present, it can be much safer to open lower with a greater chance of an offheading, than higher.

Australia has a classic example of this that is jumped frequently. The LP in the Blue Mountains (jumped first by Pete F #173 in 1995) is about 730' high and requires a running exit and 4+ second delay to clear a massive bulge in the wall. Jumping this object slider down would significantly increase the risk of an object strike.

For optimum safety on a jump, the slider configuration and delay is determined by many more factors than just the altitude. Object shape, wind conditions at different altitudes, jumper skill level, equipment and equipment configuration all play a critical role in determining the delay.

>Even people at the Petronas (1,200') went slider up and hit the building.

All (but four) of the Petronas jumps done in Aug/Sep 2001 were from 870' to impact. The jump was made very close to vertical by an exit ramp extending out from the building. Slider up jumping was made mandatory (except in two special occasions) and jumpers were required to do 4 second delays minimum for safety reasons. One jumper was removed from the event for demonstrating the inability to break the 4 second mark.
It was a group consensus that given various factors (altitude, common wind conditions, the setback at level 60, etc) slider up jumping was generally safer than slider down jumping from level 73 on this building.
As previously mentioned on this board, the reasons for the two object strikes (out of 570+ jumps) were as follows: incorrect gear configuration (p/c asymmetrically attached to bridle which caused a radically orbiting p/c which in turn induced line twists on deployment) and brake settings too shallow (factory set brake settings on a Mojo 240 which created unacceptably fast forward speed on deployment giving the jumper minimal time to deal with an offheading). No serious injuries resulted from impact with the building. The worst injury occurred on landing. It is likely that a PLF (Parachute Landing Fall) would have prevented this.

>A building is the most advanced object in most cases

There are tens of thousands of cliff jumps possible that are far more advanced than any building. At this present time many jumpers choose not to jump cliff objects that are more difficult than the average building. As the average skill level in the sport advances, this will change.

Note: On average a 4 second delay (which means you throw your p/c around 240' below exit) with slider up opening uses about 450 - 500 feet from exit to full pressurization. This figure varies WIDELY depending on body weight, wing loading, equipment, equipment configuration, wind conditions and air density (to name but a few). A slight snivel or p/c hesitation can chew up an extra 100 feet no problem.