The upcoming 1.8 release contains many new features for handling layer styles.
Very handy new entries in the layer list context menu: “Copy Style” and “Paste Style” make copying layer styles really fast. You don’t even have to open layer properties anymore.
Besides the classic QML layer style files, QGIS 1.8 supports the SLD standard. SLDs can be exported from and imported into new symbology.
One thing worth to note: SLDs can be exported from any type of renderer: single symbol, categorized, graduated or rule-based, but when importing an SLD, either a single symbol or rule-based renderer is created.
That means that categorized or graduated styles are converted to rule-based. If you want to preserve those renderers, you have to stick to the QML format. On the other hand, it could be very handy sometimes to have this easy way of converting styles to rule-based.
If you are looking for the “Symbol level” settings, they have been moved to the “Advanced” button:
The rule-based renderer GUI got a major face-lift. Just compare the 1.7 version
to the new clean 1.8 version:
Grouping of styles has been overhauled too: Using drag-and-drop, layers can be arranged into groups in a more flexible manner than previously possible.
There is also a new context menu which enables workflows such as changing the transparency of multiple symbols at once:
Symbol levels for the rule-based renderer can now be accessed via “Rendering order”.
It’s obvious that a lot of work has been put into style handling since the 1.7 release and these improvements are just a small fraction of what’s been done to get closer to the big goal: releasing 2.0.