If you have doubles of the Mew EX then trade it. If you do not have a double or triple of the card don't trade for it unless you can get it back from someone very quickly. If you have connections then trade. If not don't do the trade. It would be a good trade if you have more than one card. Rule of thumb never trade a card unless you have doubles or have connections to replace the Mew EX card easily XD.