Gray jesters are 8 HD medium-sized fey, currently in possession of a hefty LA of +2.
They receive considerable bonuses to dexterity and charisma, as well as smaller ones to intelligence and constitution. They have no natural armor, but do have a +2 deflection bonus to AC, which I suppose is somewhat more useful. Thanks to their land speed of 50 ft., they're far faster than most earthbound creatures at this level.
Defensively, gray jesters have a reasonable DR 10/cold iron, as well as SR 18. However, these two numbers are lowered considerably (to DR 5 and SR 12) if the jester uses its Empathic Feeding ability: a (Su) that lets it drain some charisma from nearby laughing or joyous humanoids.
Normally, draining 1d4 charisma from a very select group of creatures as a standard action wouldn't be very useful. However, all creatures with less HD than the jester that are completely drained of charisma by this ability become its servants (to a limit of four times the jester's HD). In theory, that means every gray jester can be running around with a party of equally-leveled adventurers under its control, but to me that's like saying Charm Animal is overpowered because battletitans exist.
A final thing of note is the jester's scepter, which is a finessable weapon that deals 1d4 points of (probably bludgeoning) damage and also causes a Tasha's Hideous Laughter effect on everybody it hits. Because it uses the SLA formula, it's DC will be very low (12 + charisma modifier), and because almost nothing you ever use it on will be a fey, creatures will receive a further +4 bonus on their saving throws.
Considering this, gray jesters are semi-useful charisma drainers who can maybe even pull off a niche flurry build to try and affect some foes with what's despite everything still a save-or-lose, but given the lack of potential targets to dominate and the general uselessness of their scepter, I'll go with a +0 here for now.