Pros.
_Some of the highest burst DPS in the game.
_Can navigate without being spotted in mini map.
_Great gank and roam potential.

Cons.
_Reliant on mana if abilities are spammed
_Has no escape until level 20 in certain builds
_Cant solo lanes without spending talents that reduce her burst potential.

ALWAYS PICK Ambush Snipe
Additional damage on your snipe when uncloaking allows you to deal more burst damage.

OPTIONAL Tazer Rounds
A 4 second slow can be very powerful with a coordinated team to make use of it especially on heroes with no gap closers. I would never pick this in solo Q though.

NEVER Conjurer's Pursuit
Nova zaps through her mana pool too fast for this talent to be useful after the patch changes it is only useful in the late game and by then your mana pool large enough to not need this talent.

NEVER Psi-Op Rangefinder
The range on your snipe is already long enough and if you go for anti-armor shells.