I'm thinking about using Gildor and his exiles but are they any good? Yes or No?

The thing about the NE is that you have to ally in the WE you want to upgrade. So you either have Gildor leading High Elves or have him on his own. Then you bring in a Mirkwood/Lothlorien hero to lead the WE. Other than that, they are great. An extra 2in of movement for only 1 point? That's amazing.

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"Leave Sauron to me."
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i had assumed you could take Gildor and that would allow you to take wood elves but with this upgrade in a Rivendell force without having to ally is this not so then?

No, you have to ally the WE in. It may be that the writers meant for him to be able to lead WE, but the rules as written don't allow it.

_________________
"Leave Sauron to me."
If you're in the Raleigh, NC area, let me know.

Thats a shame Gildor is a really great hero (powerful, reasonable costed, good special rules ect.) and the ability to take wood elves or unarmoured high elves as you could see it would really add something to the list (cheap infantry at least for elves) also in the Hobbit trailer you can see Rivendell Knights which will likely be released by GW giving you a great variety of elite troops to choose from.

I might take Gildor as part of my wood elf army then and use him to bring in the high elf defence and upgrade my wood elves