I've been hearing progressively more noise around the DSL[0] approach lately though. The OSS options might not be competitive (or maybe they are?), but performant implementations definitely exist.
[0] https://wiki.python.org/moin/Templating#Template_engines_imp...
An important sub-title which needs to be highlighted, as these arguments and micro-benchmarks do not apply to most people who use string templating server side.