No, I only bought services and hotel vouchers.

In part, I agree with Erich's answer i. E. "... seen plenty that aren't that great a deal". Candidly, after doing research and finding better choices, I no longer associate with Groupon in any fashion. I've found that this site bombards you/me with more "junk" than I'm willing to tolerate.
One final note, you specifically mention "expensive stuff..." e.g. watches that you want to purchase. You may want to check out Ashford.com. I've purchased 6 watches from them in the last 3 years ranging in price from $100. Seikos on the lower end to $2400. Rado's on my higher end. That's my price range for watches. However, since "expensive stuff" is subjective in nature, Ashford sells less expensive watches from under $100. To seriously high end Swiss watches in the 5 figure range (too rich for me...). Best of luck...

Some of the goods are worth researching online before buying. Always do your homework before making a purchase. Look for brand names and reviews on other sites, etc. I've had some good purchases come through Groupon Goods, and seen plenty that aren't actually that great a deal.