Pallas hands down!! Here are the reasons I chose the pallas over the W bag:
1) Versatility~the pallas has a shoulder strap and can be worn on the shoulder. You can also purchase a longer crossbody strap (I use my audacieuse strap for crossbody wear). The W bag is predominantly a handheld bag.
2) The price~ The pallas is almost half the price of the W bag. I think you get more for your money considering both are largely canvas bags. For the price of the W bag, you can buy an all leather bag.
3) The looks~ I personally prefer a less busy bag. I find the pallas to be a very classy bag without too much going on. It also has suede lining and a touch of leather on the top which sets it apart from the other canvas bags.
4) Resale value~ while this is always a tough thing to predict, my experience has been that when bags are discontinued or LE, I have received less money when I've sold them. There are exceptions, but given LVs crazy price increases, I think the pallas is part of the permanent collection and will increase in value as long as it's available. If the W bag is discontinued, the only point of reference is the price you paid for it.
Just my opinion, and I am sure many others may disagree with me but at the end of the day, you have to choose the bag that fits your style
Happy shopping