There has been a recent spate of reports on the nets and to TidBITS regarding warranty service on Macintosh computers through third-party mail order vendors, such as those advertising in the backs of Mac trade magazines. Some customers have had difficulty obtaining warranty service they expected for defective machines and components, often leading to a great deal of frustration, not to mention lost time and money. Though there's not enough information available right now to make specific recommendations, there are some general points to keep in mind if you're thinking about buying machines from third-party vendors:
Apple cannot (and does not) warranty any third-party accessories added to machines you order from a vendor. This includes (but is not limited to) third-party RAM, hard disks, CD-ROM drives, video cards, and so on. Any warranty or service on these components comes at the discretion of the vendor or the original manufacturer.
Remember that clock-chipping a Macintosh to increase your its CPU speed violates your Apple warranty.
Modification to or stripping down a stock Apple configuration may not be covered by a warranty, and may invalidate Apple's warranty on a machine. Say you want to buy a Power Mac 6100 without an internal CD-ROM. The vendor will probably charge you for a technician's time, but removing the drive may invalidate the Apple warranty. Be sure you understand the ramifications of any changes made to a machine by a vendor before you buy.
Examine the vendor's return policy and warranty agreement before making a purchase. Many vendors leave warranty service on stock configurations entirely up to Apple; others may charge shipping or return fees if there are problems.
If possible, use a credit card with a consumer protection plan for your purchase. In the event you do have a legitimate problem with a vendor, the credit card company will often back you up.
When contacted, Apple declined to give an official response to reported problems but noted that they generally go to some lengths to meet warranty obligations (and this has been true in my personal experience). Also, it should be noted that vendors aren't generally in the business of selling people bad machines, but they are in business of selling machines as cheaply as they can. Sometimes vendors are able to advertise lower prices because they managed to obtain a set of units that were discontinued or were originally slated to be shipped to a foreign market; other times, they may be able to offer refurbished machines at a significant discount, but with no warranty.
Always be sure you understand precisely what you're buying, precisely what the vendor's warranty and return policy is on your purchase, and precisely what your options are if there should be a problem. Buying a machine mail order isn't necessarily for the faint of heart, and though there can be some substantial deals out there, always remember that if something seems to good to be true, it probably is.