I have mixed feelings about marble countertops.They are definitely beautiful.But I would never recommend them for kitchen use.
Marble is far more porous (less dense) than granite.This makes it highly susceptible to staining.It also makes chipping and cracking more likely.
I feel comfortable recommending marble for vanities.The chances for staining and the general wear-and-tear on vanities are minimal.
A homeowner with marble countertops must be religious with sealing.Because it's more porous than granite, marble must be sealed more regularly.It's also important to wipe up any spill immediately.
However, there are products that 'suck' the stains out of stone countertops - should you happen to need one.The most common is a powder/paste product that you rub into the stain, cover with plastic wrap and leave for 1-2 days.It works amazingly well.
The extra loving care required by marble is worth it for some, not for others.
The end question for you is: How much time and effort am I willing to put into my countertop?