I downloaded and played the beta for about an hour today and here are my impressions:
Beautiful graphics for a handheld, but not quite as amazing as the screenshots would have you believe due to some pop-in and a few dips in the frame rate when using certain vanguard tech in full matches.
Graphically, Killzone edges out ahead of Uncharted as the best looking game due to the crisp native resolution and smoother average frame-rate, but it isn't quite up there with the console Killzone games, not that we can expect that.
The controls are solid, better than other Vita shooters, but certain touch screen actions like brutal melee are hit or miss and can lead to some frustration.
Shooting feels accurate and satisfying with the few weapons I tried, as does bringing down other players in a burst of gunfire from far away. But the lack of third person kill-cams is disappointing as death results in a jarring black and white, zoomed in view of low polygon geometry.
The 4v4 player cap is also a bit disappointing, but gameplay feels excellent and balanced between close quarters firefights and long range aiming duels when the game is full. The experience does diminish somewhat with just 2v2.
I think 5v5 for these maps would have been the sweet spot, where you can afford to lose two players and still have a frantic match.
Overall, I'd say Killzone Mercenary has the potential to be the best action game on Vita, but from what I've played and the trailers I've seen, the game might not hit the series plateau reached by Killzone 2. But you can't really expect that from a $40 handheld game.
I'll definitely be picking this up in two weeks.
