I have several styles of DRT and SRT climbing that I use; they've been developed in my five short years of climbing.
Having said that, however, I now state that if I could learn or teach only one style of climbing it would be the standard double-rope technique using either the 5/3 friction knot or the 4/3 (depending on the weight and preference of the individual climber). The reason for this is quite simple: the standard DRT system allows quick and safe positioning anywhere I want to go in the canopy. I can move up or down almost instantly without having to remove or add mechanical devices such as ascenders or descenders, which could quickly get an inexperienced climber into trouble.
I would only teach SRT to a climber after he or she has made a lot of climbs using the DRT system, and has reached a point where he or she feels comfortable in the canopy and can move around up there with a reasonable degree of ease. Even then, I would start with a system such at the yo-yo, which allows the climber to ascend and descend on the same mechanical devices without having to switch over.
After all, this climbing stuff is all about safety...!