I`ve been playing the Battlefield Hardline (February 2015) beta for a couple of days now and you are reading my view on the game right now. I`ve also played the first beta.

The game feels stable, I haven`t had any crashes or found/seen any bugs so far.
The graphics quality is like Battlefield 4, but slightly better. I have not run under optimal settings (using Fo Experience), I ran under High Quality settings.
The game runs smooth on my 3-year-old pc and that is a big plus.

The game itself plays much quicker than BF4, it`s more arcade action as BF4 was more realistic. But still, who doesn`t want to play bank robber or cop? My favorite game mode out of the two so far (Heist or H) is definitely Heist.
The maps are like all Battlefield games beautiful and detailed. The bank map looks awesome and the diversity of buildings, rooms, open spaces is well divided.

To end this  mini beta review, my tactical ingame advice when you play with a buddy: Arm one with a zipline and the other with a grappling hook. Together you can climb any building and use the zipline to move between places quickly.