Sony Vegas Pro 12's effects chain system makes it possible to combine multiple effects, but it takes some learning to master properly.
Little about Vegas's interface has changed since I last sat down with the program a couple of years ago. It has the flavor of a mid-2000s-era Windows app (such as toolbars and panels that can be docked in tab sets), but it's designed to be functional, not flashy, and it isn't difficult to navigate or use.
A feature I liked in previous editions of Vegas was the excellent guided help, which is still here. Choose a tutorial (such as "How to add audio effects"), and Vegas will walk you through each step of the tutorial, letting you try it out it with whatever project you're currently working on. That way you're not just reading a set of instructions, but you're actually using the function, which is enormously handy for complex and multi-step processes.
As with Premiere Pro, a few of the new features in this version of Vegas Pro are designed to appeal to editors coming in from professional-level suites like Avid. These include the ability to see edit points in a split-screen A/B view and to trim either side of the edit interactively while playing that region in a loop. Likewise, new keyboard shortcuts let you trim parts of just the video or audio track in a selection, making it easier to create common cinematic effects like cutaways or overlapping audio.
New to Vegas is a masked-effects function. This means that effects applied to a video clip can be constrained to only parts of the image -- for example, blurring out a face. There's a steep learning curve involved, since you have to learn about a fair number of different functions at once (such as the effects chain system and the way masking works), but once they're mastered a great many things become possible.
Aside from Vegas's native effects system, the suite version of Sony Vegas Pro includes HitFilm 2 Ultimate, which is akin to Adobe After Effects. HitFilm generates a wide array of visual effects: color processing, particle and lighting effects (rain, smoke, muzzle flashes), and so on. Like After Effects, HitFilm is an application unto itself with its own workflow but, unlike After Effects, HitFilm's interface differs rather radically from its parent program. (HitFilm is not made by Sony, but is a third-party product.)