Not if it's an expensive watch. There are way too many counterfeits sold on eBay. There are very honest sellers on eBay but it's very hard to tell who they are.
I have purchased many things on eBay. Here are some things I look for:
Must be an established seller with a rating of 97 or above. You can click on their reviews and see if someone has filed a Negative or Neutral review to see what the problem was. Many sellers are 100% but sometimes you get one negative review and it drops your rating down. You can also see when it was (like in the last six months or so).
Research the item you want to buy. If you want to buy a Rolex watch that normally costs $600 and you can get it for $30 on eBay, you must ask yourself, is that a reasonable cost for this type of item, or am I being screwed?
Check out the return policy. Not everyone accepts returns and not all transactions quality for eBay's Money Back Guarantee. You want the ability to return the item and get your money back if the item is not the quality advertised.
Lastly, ask yourself if you'd rather see it, touch it, examine it in person or do you want to take a chance on photos of what you may be getting? If it's an expensive item, you might want to handle this in person and not through a website. Hope this helps.
I'd say no . I would buy a watch, probably from Amazon.