Stock JB rom has a nice feature of things getting out of the way when you add a new widget or rearrange things, but it doesn't support rotate (portrait vs landscape).
Nova reportedly is better for marginal hardware (old devices) and seems to be better at helping restore apps if you wipe and restore via TIBU or similar backup program. It'll have a "tap here" to restore your app.
Apex has merged JB code in their latest beta and appears to be trying to add the JB features all these launchers lack.
Only the stock launcher is missing the rotate feature.
Non-stock launchers have a long-press menu that allows you to add widgets, shortcuts, etc.