I've used them all. Here's my take:
S-33 is not Belgian at all and the only "Belgian" style it's suitable for is Belgian Pale which is notably lacking in phenols and esters. It works extremely well for a hazy pale or IPA where slightly higher FG is acceptable. Low mash temps and a sugar feed on the second day of fermentation helps ensure full attenuation. Clean and almost lager-like at low temps but it really adds mouthfeel and can accentuate certain lemony/citrusy hop flavors and aromas.
T-58 if a fairly bland Belgian strain with a "Juicy-Fruit gum" sort of flavor. It'll develop some clovey character but not as much as the trappist yeasts. Attenuation can be very good but it likes starting a little low - low 60s - and ramping up relatively quickly to 70 or more for finishing out. Good candidate for Belgian IPA because it doesn't get in the way of hop flavors.
BE-256 (used to be Abbeye?) is much more traditional Trappist flavor. Definitely more clove and fruitcake flavors. Great for big, high-octane Belgian styles. I don't use those yeasts much because it literally induces indigestion for me.