For the most part, SainSmart has been pretty good to me with their Mega2560 boards. Heck, I sell them myself.... =) I think vreihen is correct on most, if not all, of the complaints regarding SainSmart. They are a big time manufacturer from China and they produce Mega boards by the thousands at a time, and I honestly don't think they test each one, as it's simply not cost effective to do that. I had ordered a few SainSmart Mega2560s in the past and I can remember having issues with 1 or 2 out of the lot of 10. But they were minor issues, primarily not having the Arduino bootloaders on them already. So, since I test all of my boards (yes, each and every one!) prior to shipment to clients, I was able to correct the issues and simply flash the boards myself.
When it comes to their RAMPS 1.4 Boards on the other hand, I was not very excited when I first got them. Just like vreihen's issue with his/her Megatronics board from SainSmart, mine did not come with any jumpers! How ridiculous is that? My first thought was that "I hope they know that the jumpers are NECESSARY to operate my machine!" That just told me first hand how much they know exactly about RAMPS... =) Secondly, some of the female headers on the board for the Stepper Drivers were CRACKED! I was going to buy a wholesale lot of their RAMPS to re-sell, but just decided to make them myself. I thought that my clients would be a lot more happier and would have a lot more confidence if they could deal with someone who actually makes these boards here in the U.S. For the most part, I was right.... =)
When it comes to their RAMPS 1.4 Boards on the other hand, I was not very excited when I first got them. Just like vreihen's issue with his/her Megatronics board from SainSmart, mine did not come with any jumpers! How ridiculous is that? My first thought was that "I hope they know that the jumpers are NECESSARY to operate my machine!" That just told me first hand how much they know exactly about RAMPS... =) Secondly, some of the female headers on the board for the Stepper Drivers were CRACKED! I was going to buy a wholesale lot of their RAMPS to re-sell, but just decided to make them myself. I thought that my clients would be a lot more happier and would have a lot more confidence if they could deal with someone who actually makes these boards here in the U.S. For the most part, I was right.... =)