On the enemies meleeing you when you SS, I've noticed that sometimes if the lag works out right, you can see your character stand next to the enemy as soon as you cast, but doesn't "officially" uncloak until the animation reaches that point. I'm pretty sure the game transfers your position there before the animation. The enemy then will likely riddle you with a few bullets before using its melee if it had detected you when you SS. It's also much more noticeable than charge because charge makes you temporarily invincible (if I remember right).
What helps is cloaking out of sight/waiting until you have broken their sight on you if you cloaked where they could see you, and then SS. If you take the bonus power use on SS, you'll still be cloaked afterwards. Also, always SS the outer edges of a group. Inside of a group, someone will probably run into where you are/will be and suddenly everyone will gun you down.
Which leads me to this question:
If you take the bonus power use on cloak, do you count as uncloaked when you SS? There's that bit where she dips out of cloak, strikes, and then goes back into cloak. Is she vulnerable during that second she appears out of cloak or does she register as cloaked that entire time?