Here are some tips from my experience with Godaddy Auctions:
1. If you're serious about finding a good domain with traffic, stay away from bargain bin and closeouts.
2. Stick with the expiring domain auctions. That's where you'l find the real "bargains"
3. The traffic numbers are pretty accurate. Some domains will be bring you monthly what Godaddy lists in the auction, others will bring much higher traffic than listed.
4. The traffic I have found does include bot traffic. The traffic estimations include all type of traffic. So you need to take this into account when bidding.
5. There are many metrics you need to look into before deciding which domain will be the best to bid on. One hint: check out how many bidders a particular domain has - that's a big clue on the value of a domain that's up for auction. But that still doesn't mean it's the right domain for you to pursue. There are many other methods we use to determine whether a domain is worth pursuing.
Finally, I can tell you we've nabbed some great domains with traffic from Godaddy auctions, and some not so great. Some of these domains began sending us Adsense clicks just days after we developed the domains.
We recently won a domain at auction with a pagerank of 4 and some .edu inbound links.
We develop the domains into websites and mirror as closely as possible the content that used to be on the domain.