The following is based on the post here in the TCW review thread.
A ~135m long and roughly tubular-shape Republic prototype vessel is cloak-capable in the episode "Cat and Mouse"[TCW2]. The vessel's volume is perhaps 4000 cubic meters given its length and slenderness (the design reminds one of the Discovery from 2001), implying that it may not be significantly more voluminous than the Falcon or Twilight. This may suggest that length is somehow critical for cloaking, given that no ship as small as the Falcon is supposed to have a cloaking device per Needa in the original trilogy.
Regarding the capabilities of the cloak:
a. No visual distortion, even when touched on the hull by a Jedi hand.
b. No detection by Separatist ships (including Munificents, a Providence, and Trade Federation battleships) using standard scanning despite a hull-grazing pass of a Munificent. Even when the presence of the cloaked ship was known and the vessel had recloaked, scanning was ineffective until Separatist Admiral Trench's magnetic signature trick was employed. After that they had the ship on sensors without difficulty.
c. The ship cannot fire any weapons while cloaked, including "torpedoes and anti-aircraft cannons". When preparing to decloak and fire torpedoes, mixed within the torpedo firing prep lines was a note about diverting power. This may imply that Star Wars cloaks can't fire due to cloaking device power drain.
d. When detection was feared due to a close pass by fighters and bombers, Anakin ordered all systems and engines powered down save for the cloak, implying the possibility of some sort of signal leakage when these systems were functioning.
e. Cloak activation/deactivation requires only a couple of seconds, involving a luminous blue sparkly-bolt effect like electric arcs over the hull. However, after cloak deactivation, 15-35 seconds is apparently required to reactivate the cloak, at least after firing a full four-tube torpedo volley (it was 35 the first time, 15 the second).
f. Per Admiral Trench, any stealth ship could pass the Separatist blockade easily. This strongly suggests that cloaking devices are both rare (otherwise no one would bother to try to blockade) and rather effective (otherwise they'd be able to detect them readily).
And, though I neglected to mention it in the other post, yes you can see out from inside the cloak.
Basically, the cloaking device is akin to what one would expect from watching Star Trek IV: The Voyage Home.
The Separatist admiral had used "tracking torpedoes" to destroy cloaked cruisers in prior engagements, but he'd only had a few engagements with cloaked ships, and the description suggests these ships were large cloaked vessels. All signs point to cloaking being sufficiently rare that these battles were few and far between.
His use of tracking torpedoes to destroy cloaked ships seemed confusing to the Republic, which apparently never determined how he did it until now (the magnetic signature issue that Anakin guessed).
So, now we've seen it. Thoughts and impressions?
My view is that we're clearly seeing Star Wars cloaking tech being well behind Star Trek cloaking.
Borrowing from Chakoteya:
In other words, only when the Romulan cloak was intentionally screwed with would you get a magnetic signature, and even then only when the ship was in motion.N'VEK: There is one possibility. In order for a ship to remain undetectable while cloaked, the radiative emissions from the warp engines must be precisely balanced. The ship's Engineer is a sympathiser. He may be able to slightly misalign one of the nullifier cores. It would create a small magnetic disturbance in space whenever we were in motion.
TROI: Good. Do it.
N'VEK: The effect would only be intermittently. They might not even detect it.
TROI: If it's the best we can do, we have to try it.
N'VEK: Anything more would be immediately registered on the Bridge. Even this slight misalignment may be detected.
Counterexamples welcome.
