I was skeptical when i heard this brand name, never really heard before and all-in-all a completely unknown brand, but it was my only option as i was on a tight budget. I still regret my decision and wish i could have gone with intel oem mobo but it was twice the price though i did had the chance but i went miser.
Initially, i was thinking about getting DB75EN which has all good features such as SATA 3, USB 3.0 and PCIe 3.0. But the price online was quite ridiculous (especially on amazon). So i thought to get a cheaper option such as the one originally came with my PC, DH61WW. It was priced around ₹3,500 (54$) few months ago (i think around in august) but due to some heavy fluctuation the price went double and currently it is selling for ₹7,000 (108$). It has PCIe 2.0, USB 2.0, SATA 2 (quite older technology). But the one mind boggling feature was it has fully functional UEFI BIOS (which were released for it in a bios update around the launch of Windows 8).
I consider myself unlucky for ones that the initial replacement from Gigabyte (H61M-S) i got had a manufacturing defect which would cause it to stop booting after BSOD crash of changed bios settings from IDE to AHCI or vice-versa. Mercury is really an amateur motherboard manufacturing company and it shows in their work and effort to manufacture these motherboards.
One of the review on Amazon India of their PIH55Z motherboard says (1 star rating review) :
First of all this mercury pih55z is a mini ITX motherboard with all the essential features cut-off, It is the worlds tiniest motherboard I've ever seen, square shaped, probably the size of my stretch Palm !!! It comes with no features at all. It is a basic motherboard like Raspberry Pi , It comes with American Megatrends Bios (AMI Bios ver080015/v2.67) which is the worst bios ever .Most of the important settings( like CPU Frequency , CPU/Ram voltage ) are locked and hidden. It has a bad OEM Lock, so you can't use Intel turbo boost' technology and locks your CPU speed to low and stock !!! It has only one 4pin CPU fan connectors, there is no provision for any other System fans . It just is plainly rubbish and has a misleading title saying " Extreme " but is a basic board like raspberry pi and has no basic features that a H55 lga1156 socket motherboard should have !!! Overall avoid buying this, it is worth less than Rs.500 actually it is not even worth buying for 1ruppee. Avoid , Mercury is an inexperienced manufacturer that doesn't know what a motherboard is !!!! Don't buy , I bought from amazon.in from a seller called Comfortliving (a.k.a Gamebox) , the product sucks and is the worst mobo I've ever seen !!! Although Comfortliving delivered good service , Mercury and The bios are the worst parts, No proper CPU support for Intel CPU with turbo boost .... Don't buy unless it is Intel celeron or pentium... In short buy a MSI or Asus Motherboard , this is not a motherboard for an i5 or i7 though it says it supports, driver issues are the worst, no driver available at Mercury.com only CD drivers which don't install at all....this is one of the worst motherboards...
Original Review : Do not buy this at any cost , it sucks.!!!