Answers based on "the syntax is hard" is no answer at all imho. A). It really isn't, and B). You're supposed to be a programmer, just learn it.
Definitely other technologies are advancing at a pace XSLT hasn't since 2005ish, but it remains a powerful tool which gives you a level of abstraction that, say, asp.net webforms don't, and allows you to provide a general scalable solution to trivially serialise to a range of output formats. It's easy to generate HTML with any given language, it's harder to now extend that to XML, now extend that to JSON, now extend that to CSV.
And cached transforms are plenty fast enough in an environment which is still I/O bound.
OTOH, storing data in XML is generally not a good idea. Far better to store in a DB/mem and serialise as required for all the reasons above.
