I started with a 300EX a couple years ago and now have a 400EX and the 300 is my wife's bike. On the trails we ride, the 300 usually the better bike. Not quite as fast in balls out driving, but so much softer and more comfortable for a long day of riding. But the power limits prevail on the higher speed trails. After some time with 400, I don't care for the 300 anymore. It's comfy, but not worth it if I don't have the same kind of fun. Warrier or 300EX are my picks for starter bike. Almost no maintainance and trouble free for years. I recommend picking up a used bike, stock, though. Stock = reliable. You can buy a 300EX for $2500 and sell it next year for the same money when/if you decide to upgrade. Buy a new 300EX for $4200 and get $3200 next year.
Weight of the rider and what type of riding you do matter, though. I'm only 175 pounds so the 300Ex can be fun. The 400 is quick. If you weight 50 pounds more, a 400Ex might feel to you like the 300EX to me.
