i purchased a mangalsutra from www.allyoursjewels.com . most of the things were as per the description, only the delivery time took a bit of more time than expected.
Best part is the delay was compensated with extra service by getting my old jewellery refurbished for free!
one year insurance, door step delivery, customization, recognised company with global presence etc are some of the unique feature i find with them.
over all it was a good experience buying from Allyours jewels. i recommend them.