Here is a few videos showing some beta gameplay. The first video is a video of a Level 50 Mercenary Bounty Hunter doing PvP in Star Wars: The Old Republic. The video have has some insightful commentary that I personally enjoyed. The guys that made the video is using real PvP situations to illustrate the classes strengths and weaknesses.
If your thinking about creating a Bounty hunter with tne Mercenary tree, I also recoment you to check out this short video. This video is A beta overview of the Bounty Hunter Mercenary advanced class’ main damage dealing spec, the Arsenal spec, at level 50 in SWTOR with gameplay footage. This is the same as the Commando Gunnery spec, with different ability animations and names
And finally here is a video of a Level 50 Mercenary Bounty Hunter (Arsenal spec) soloing 2 named boss-level mobs at the same time, wich hopefully should give you a good idea of how the Mercenary plays in solo PvE content.