The one you buy really depends on what type of projects you will be doing.

If you will be using lots of effects and require easy keyframing, then premiere will do a good job and is easy to learn, as there are lots of tutorials to be found on the web. But premiere does require lots of rendering to get good smooth playback of effects and transitions, and gets grumpy if you have long timelines(45mins plus) especially when exporting.

I have used 'Pinnacle' liquid pro 6 briefly a few years back and it seemed to me to be more geared towards broadcast style editing, longer timelines, less customisable effects but less rendering, good quality output, even on lower spec machines and even back then it had multicam editing.

Hopefully it has been improved since going to Avid, but you would need someone who uses it to give advice on this, as my knowledge is limited.