I rarely hear of Apple support that is not great. In any case, you always get a native English speaker who knows what he's doing, not an unintelligible Indian running a checklist. As to whether the $250 is worth it, that's always a gamble with anything. The Equipment's generally good quality, and Apple been known to support out-of-warranty equipment.
To compare, Dell gives you a year hardware support standard, same as Apple. For the software, you'll get better support than you do with Windows. The only sticker is that in a few years Apple will likely not be actively supporting your version of the OS anymore, and you will need to upgrade to stay current. In the past upgrades cost $129, but lately they've been $39. I've upgraded 10.4 to 10.5 to 10.6, and it's been brain-dead easy all the way through.