Glade Guard are an excellent unit to include, they are fine shots and at short range they deliver str 4 hits.
You often see games with, say Empire handgunners when, they know that they will get one last shot in at short range before they will be routing off the table. Well, this needn't be the case with Glade Guard and that's what makes them so essential to the Wood Elf army.
I have seen Glade Guard units survive a whole battle by jumping in and out of Woods and picking the enemy off (slowly but surely) with short and long range bow fire. Even without the presence of any woods, the Glade Guard, like all Elves are tough to pin down and require cavalry or flyers to stop them from wreaking a kind of slow death mounting havoc in your army.
I would always include units of Glade Guard in any Wood Elf army.
note: Glade Guard only, Waywatchers do not have the same type of super-strong longbow wood :)