Generally, being seen means you are effectively screwed unless you are a very good player. If you see an enemy ESF hovering and looking right at you, GTFO to the closest hiding spot. HS/NV scopes and some vehicle Optics (such as ESF and Liberator Thermal) will also be able to see through your cloak.
Darklight Flashlights hard-counter camping Stalkers which hide out in the capture range of Capping Points.Your cloaking sounds, if you cloak/decloak, can be heard from a distance and the sounds are different for each faction, meaning that experienced players will know there is an enemy Infiltrator nearby.Shields and Health do not regenerate while you are cloaked (although the timer before your shields begin recharging after taking damage is counted down).This includes shooting, hacking, placing Recon Darts, Motion Spotters, Squad Beacons and AP Mines, using Medkits. You cannot do various things while cloaked.
The Cloak recharges faster while you are decloaked, promoting the idea of using it like a Hunter Cloak (bad for newcomers and transitioners from Hunter to Stalker, may create bad habits).This means no Snipers, no SMGs, just Sidearm, Tool and Utility. Most importantly of all, your primary weapon slot is disabled ALL THE TIME that you have the Stalker Cloak in your current loadout - not just while you are using the Stalker Cloak.It's absolutely awesome for trolling or annoying other players and good for laughs if you watch people spraying their weapons, trying to find you, or they run right past you.
It's still useful for the baselines, though.
As I haven't played PS2 in a while and a lot of content relevant to Stalker Cloak Infiltrators has been released, from buffs to nerfs to new weapons etc.