What are the Advantages and disadvantages of just-in-time supply
relationships from an organizational buyer's point of veiw?

The advantage of the JIT delivery from the buyers perspective is the
ability to have inventory readily available, but not have to purchase
it untill you need it or sell it. Then your terms (net 30, net 60 or
whatever) dont start ticking untill you order the product.

Also, there are some tax advantages of being able not stock much
inventory. At the end of the year, it's easier to 'empty the
warehouse'.

The initial cash outlay of housing an inventory...orders are placed at
suppliers as orders are received.
The costs such as inventory, storage, depreciation costs will be at a minimum.
You could have no storage at all...place orders for all product once
you have rec'd them from your customer.  Dated inventory can be
costly...ie. the electronics industry...while the latest product is
hot....a costly inventory of those that do not/will not sell because
the next "latest" product is now desired by the consumers...this could
result in a liquidation inventory sale...at your loss.
You do not have to depreciate inventory that you do not "physically" own.
You won't tie up any of your cash on inventory waiting to sell.