Like many of the other reviewers, I found TigerDirect's biggest fault was the terrible customer service.
I ordered a motherboard & CPU bundle as well as some other hardware items for a new computer I was building. I placed the order by phone as I was having severe problems with their website. I never received an email confirmation of my order or any shipping confirmation. All my items were in stock. When I didn't get confirmation for 48 hours I called customer service and was told that their distribution center (somewhere in Illinois) was undergoing inventory and no orders would ship until it was finished in about 2 or 3 more days.
I was furious that I wasn't told about the delay when I ordered. I must have been speaking to a representative with some decency because he let me in on the inner workings of their operation. They work on commission. If the rep who took my order was honest I might not have ordered and he would have lost his commission. What's more, if you return an item or items the rep loses the commission. So it's in their best interest to withhold information, lie or stonewall you for as long as possible since the return period on your order is 30 days from the date you ordered not when you received it. If they string you along past the return date you get stuck with the defective, unwanted, etc. merchandise and your friendly, helpful rep gets to keep their commission.
Don't be fooled by the good prices. Don't be taken in by the great catalogue. This company is based on what amounts to high pressure sales. They will do whatever is necessary to get you to make and not return an order since the company has set up their sales people like boiler room telemarketing salespeople who must sell or starve.
There are lots of other good internet computer hardware vendors like Compuplus, Computergate or Silicon Valley Compucycle who gave me great prices (better than TigerDirect) and excellent service even talking me out of buying a product I didn't really need.