Well, I'm well-known for my bottom-feeding on ebay.. and if the device being made was critical in any way, I would use "real" parts purchased from a reputable retailer.. but in reality, almost none of my projects are something I would directly sell or depend upon for any real purpose. I will buy "as-is" and "NOS" as a priority, knowing the risks. The fact is, I feel more comfortable buying from a Shenzen seller with twenty thousand sales on ebay than I do with a Los Angeles seller with sixty sales.. I trust the Shenzen volume seller to care about their reputation more than the new account from California.
In the years I have been grabbing ebay dregs, I only once have gotten trash- a four pack of ATMEGA88's that wouldn't do a thing- and the seller refunded.
"polida" (the vendor for this particular deal) is one that I have bought a number of things from- and if you don't need customer service (language barrier) I haven't had any problems with and tends to ship pretty quickly. I think their angle is sheer volume, if you look at their total number of customers it's in the tens of thousands.
Happily, most of these vendors seem to know their customers are going to be hobbyists and the like- they tend to have a lot of the stuff we tend to buy. Modules of various types (sensors, voltage regulators, SD card, ethernet, etc) can be ridiculously cheap- I have gotten ethernet modules for $3, Bluetooth for $2, and stepper motor controller (ULN2003) plus stepper motor for $3. Outside of the modules, you can always bottom feed on certain items- 2N3904/3906 transistors, ULN2003A Darlington Arrays, LED's of all types, MOSFET's, and a dozen different "uino" clones. I had to dedicate my "real" Arduino Duemilanove to a project for a couple months, so I decided to give (reference to counterfeit product removed by moderator) a try.. they are one of the larger clone outfits. Their prices are hard to beat also, I got a Uno clone, a Proto Shield with 65 jumpers and a mini breadboard, and an LCD keypad (looks suspiciously like liudr's design) shield... all of it for $39 shipped. It's coming from California, so shipping isn't even the couple of weeks of waiting that ordering from China is.. it's just the normal 2-3 days for mail. Today, I am making a 24-channel PWM controller (8 channels of RGB) using AT90S4414.. I bought two TUBES (twenty MCU's, 40-pin AVRs) for $7 TOTAL a while back (I just realized to myself that amounts to just over a penny per GPIO pin!). I have been planning to using them to make quick and dirty SPI-to-1602 LCD interfaces, should work great for the purpose. I am still looking for a good use for the half tube of Dallas 12887+ clocks I bought for TWO BUCKS also. Yes, I know all of these components are likely to be factory seconds or overstocks- but as I said- in several years and dozens of purchases, only ONE has ever been outright bad. One thing is for sure- the vendors take take "Feedback" very seriously and will bend over backwards even on a deal to avoid getting bad feedback, it seems. I wouldn't try to "take advantage" of that, but it does seem they care about those stars a lot.
I will give a report on the (reference to counterfeit product removed by moderator) "uino" when it arrives- but I see no reason for it to be anything other than a good ole basic Uno..