I won several items several times from Bidz.com, and here is my review:

Good thing:

- you may get lucky and get the nice item that you like for a lower price than the mall (after discount) price.  I won a nice white gold bangle one time that motivated me to bid more   

- many bids will finish in 2 days, so you don't have to wait longer (like with ebay we can wait for 7-10 days before the auction finishes)

Not a good thing:

- many items don't have enough details on it, it's like bidding and gambling at the same time, if you think it's enough just by looking at the picture, well I learned...