IBM just isn't playing in the same league as those three companies mentioned above (if we're being brutally honest based on experience). They deal with complaints constantly (check out these recent ones; they supposedly used to be better). That doesn't mean they're untrustworthy—I actually recommend them quite often myself—but if we’re being strictly precise, their service isn't top-tier compared to the best of the best.
Matthew Alvarez said:if something isn't available, they provide high-quality alternative solutions.
I really can't agree with that; in fact, that might be their biggest weakness. At least from my own experience with everything I've ordered, they have NEVER provided the best or most cost-effective alternative when an item is out of stock. It was always something subpar (like a more expensive, inferior DDR3 graphics card) or just whatever they happened to have sitting in the warehouse at the moment. One guy once sent a request to all the relevant shops to build a PC within a specific budget; the guy from Future sent the best proposal, the runner-up was Best Buy, and everyone else (IBM, Centro, etc.) suggested incredibly overpriced and inefficient components.