Wood looks the best!
Synthetic is more durable! (and waterproof too)
So... do you want something to look pretty, or to work hard?
Some factory-provided synthetic stocks are just pieces of junk!
The synthetic stock that came with my .338 Win. Mag. Browning A-Bolt was of such cheap & cheesy quality that you could wiggle-wag the forend from side-to-side. I replaced this stock with a Bell & Carlson, which made a huge improvement.
If I got the wood stocked model instead, I know that I would not have had this problem, because it had a more substantial forend.
If you choose wood, the most important thing that you can do is disassemble the rifle and seal all of the bare wood, such as the action, barrel groove, under the butt-plate, etc., with something like Birchwood Casey Tru-Oil.
When the wood is all sealed up it will keep moisture and cleaning oils and other gunk from soaking into the wood, which is not desirable, as it can cause the wood to swell, thus making your rifle have inconsistent accuracy, or cause rust to form in the moist spots, or in the worst case, cause your stock to swell so much that it just completely ruins it.