Standpipes are fragile and vulnerable, an accident waiting to happen. When...not if...they are struck by an errant elbow while working in the tank, or in some cases even by a large boisterous fish, they can break. If of multipiece construction, one of the seams can crack, draining your tank all the way down to that level. If a single piece, a similar blow near the top can exert a lot of leverage at the bottom, damaging the seal at the glass bottom and draining your entire tank. Either way, repairs involve draining the tank dry and replacing...with another fragile, vulnerable tube.
Drill the side near the top, use a bulkhead in conjunction with some combination of 90's, 45's, whatever. This is not only shorter and less fragile, but even if the worst happens and it is broken, your tank only drains down a few inches. You can also repair or replace these without completely emptying the tank.
If you prefer to draw the water from near the bottom, it's easy to use a T or a 90 to extend a pipe down to whatever level suits you. Also very simple to arrange for a small amount of surface skimming. Plus, they take up much less of the valuable real estate in the tank.