  We highlight certain key achievements in experimental work on molecular,
colloidal and granular glassformers. This short review considers these three
classes of experimental systems and focusses largely on the work of the authors
and their coworkers and thus is far from exhaustive. Our goal is rather to
discuss particular experimental results from these classes and to explore
universality and specificity across the broad range of length- and time-scales
they span. We emphasize that a variety of phenomena, not least dynamical
heterogeneity, growing lengthscales and a change in structure, albeit subtle,
are now well established in these three classes of glassformer. We then review
some experimental measurements which depend more specifically on the class of
glassformer, such as the Gardner transition and some which have been
investigated more in one or two classes than in all, such as configurational
entropy and evidence for a dynamical phase transition. We finally put forward
some open questions and consider what could be done to fill some of the gaps
between theoretical approaches and experiments.
