I'm not sure how to feel about the visilight conceptually. On the one hand, the idea of an alien-looking, face-stealing, paralyzing outsider is really cool. On the other hand, I don't really like how they get the lawful subtype for no real reason, and feel like the execution could've been better. Also, ability drain before level 7 is just kind of harsh.
On to the monster: visilights have reasonable stats, with +2 to +4 across the board. They're medium-sized, have 5 outsider RHD, and fly at a speed of 30 ft.
Defensively, they have +7 natural armor and DR 5/chaotic: two reasonably useful traits. Offensively, they have two 1d6 claws which are mostly pointless (the description, meanwhile, describes their attacks as 'flailing with powerful fists').
The real reason to play a visilight is their special abilities. Telepathic Link is plain useless in 99.9% of cases, but the others definitely aren't.
Firstly, there's Gaze: your typical save-or-lose paralysis gaze. The duration is a bit short (1d4 rounds), and not everything can be affected, but paralysis is a crippling debuff. However, for party-friendly reasons it's probably best to invest in Narrowed Gaze.
Secondly is Charisma Drain, and it's... problematic. The intended use: a visilight grappling and pinning foes to drain a foe's charisma and increase its own is not too likely to succeed, because even with Improved Grapple and a small natural strength bonus the visilight is just not that great at grappling.
The problem is that this ability can very easily be abused. Imagine, for example, a visilight who takes Leadership and proceeds to drain his followers of charisma, or a visilight summoner who drains his summons, or just a visilight pairing up with some Naberius binders. All of those methods allow for virtually limitless charisma that sticks around quite long, and virtually uncapped charisma is, in fact, problematic.
With this in mind, an asterisk seems in place. Charisma Drain's intended uses wasn't super relevant in-combat anyway, so I'll disregard the entire ability for the purpose of the rating. An argument could be made for both +0* and -0*, but ultimately I think that being human-shaped, blessed with good HD and stat boosts across the board, and in possession of a spammable save-or-lose makes the visilight barely eligible for a +0*. Do discuss!