Florin made a head to head comparison of Seeed and ITead’s inexpensive PCB services. He made the orders with the same design files, on the same day. While the Seeed order came in after 4 weeks, ITead’s came just 15 days after the order was made. The author however suspects it might have been a fluke, since all his earlier orders from ITead took around 4 weeks to complete too.
In Florin’s opinion the quality was identical. In the high resolution pictures it appears that the Seeed boards have better silk screen and drill positioning. This is odd because they came from the same PCB fab unaltered! Perhaps a cheaper service, or just general inconsistency between batches or boards?
Read the full comparison on his blog, along with super hi-res pictures of the boards.