When I started using Ableton Live I used the “Intro” version and was quiet happy with it. I though to have all the features I needed. I was wrong. In Intro you’re stuck to using premade Drum-/Instrument-racks and you cannot build your own. This alone may be a reason why you should upgrade to “Standard”.
I found this great article on dubspot which gives all the good reasons and there may be more:
- Your Controller Loves Racks
- Getting Exact Control Over Parameters
- One Knob, Many Tweaks
- Finding Your Signature Sound
Check out the details and decide for yourself.
-mE
productivemonkey 
Even better: Suite! Although I don’t use the stock sounds, there are some great effects that come right out of the box.
True! Some of the stock sounds are cool, but I don’t like to hear them from other producers š FXs are great like the amp simulations or the instruments included.