I just recently discovered GroupService, but I don't know how it works exactly.
For example, if I wanted to check if a player's in a certain group; there's player:IsInGroup(Id), but from what I read it caches.

How would I check with the new service? My current idea of how it's done is

local GroupsPlrIn = game:GetService('GroupService'):GetGroupsAsync(Id)
local IsInGroup = false

for i, v in next, GroupsPlrIn do
    if v.Name == 'Example_Group' then
        IsInGroup = true

if IsInGroup then
    print('Player\'s in group!')
    print('Player\'s not in group!')

But it doesn't look quite right to me. :P