Situations similar to yours are the one significant reason I think twice about recommending a refurb for some folks.
Refurbs can be a crap shoot, since you don't know *why* it was returned (or even if it was ever sold to begin with) and more to the point, what was fixed or addressed to make it "like new" again.
Intermittant failures like the one you experienced with the optical drive are almost always likely to slip through on the re-evaulation (refurbishment?) process back at the mothership, whereas a blown power supply would not since it is an obvious problem with an obvious solution.
I seriously wonder how much time is spent on each "refurbed" machine before it "passes" and is put back up for sale. I have had several refurb machines over the years that have arrived with subtle but significant hardware problems that crop up eventually. If they are discovered BEFORE Applecare runs out, they are usually fixed after jumping through the requisites hoops and investing a not insignificant amount of time narrowing down the problem to "hardware only". What bothers me most is that depending on how you use your Mac, you mght not discover these problems (or recognize them) until AFTER Applecare expires.
1. More than a year after buying my current MDD, I discovered the "audio in" port was fried... but not until I needed to use it with some audio recording software. That was the only "minor" problem I had with the machine, but since the port had been unused by me until that point it made me wonder if that was why it had been "sent back" originally and if in fact any attempt had been made to identify and fix the problem. By the time I detected the problem, I was facing a motherboard repair on my dime, or buying a USB device for audio input. I obviously went the USB device route.
2. A client ordered a refurb PowerBook G4 (800Mhz) and was very happy with it for almost 2 years before deciding to buy an external FW drive for backup an storage. Only to find that the FW port on her otherwise perfectly good laptop didn't work. Oops. Again, port hadn't been used until then.
3. Another client purchased an 800Mhz iMac G4 17" refurb. It came with factory installed 256MB of RAM which worked fine until they wanted to upgrade to Tiger and the new iLife. When it came time to add memory to the user installable SO-DIMM slot, they discoved that ANY memory added to that slot (and three different sticks were tried) caused the machine to become unstable and crash. Again, no problem *until* something about the stock configuration was changed, making the latent problem apparent.
Now, I'm not saying these same problems can't happen with NEW machines too. They can and do.
My point is that refurbs are more likely to have at some point had some problem, that resulted in them being returned. Whether that problem was *actually* detected and corrected by the technicians back at Apple, in my mind, is still a big question mark. How much time does a tech spend chasing down a "phantom" problem before slapping a refurb sticker on it and putting it back on the shelf? I don't know, but my anecdotal experience suggests that it is not rare that something slips through.
Now if it is *detected* within the AppleCare period, it is an annoyance, but it is usually fixed by Apple. Otherwise, if it slips beyond a year before being detected it is both an annoyance AND can be an expensive problem.
Maybe the solution is to buy the refurb, but ALWAYS buy the extended warranty? But if that is the case, it kind of minimizes the bargain of getting a refurn Mac... especially if you don't get the most current software packages with the refurb.
Now when I purchase a refurb for myself or someone else I check *every* port and feature I can think of before it goes into regular service. Even then there are parts that aren't practical to check (bad ram slots, etc.).
So to summarize, I guess my current approach to Apple refurbs is "trust but verify."
They can be a good source of a deal on a "new-toyou" mac, but keep in mind that they were 'refurbed" for a reason, and there is a good chance that depending on the nature of the problem, your deal may come accompanied with a little "surprise" down the road if the Apple techs didn't catch it before sending it along to you. Caveat Emptor.
It would be nice if each refrb came with some "provenance" documenting why it was refurbed and what, if anything was fixed. But that would shatter the illusion that these are truly "like new" so I don't expect to ever see it happen.