both have their advantages, but its really a personal preferance.
live advantages: reduces nitrates, fish snack, more natural, reduces algae, less chances of fish getting hurt on sharp points on plastic plants
live disadvantages: fish can snack too much, some snails eat em, have to care for them, may die, may look crappy sometimes
plastic advantages: always look good, cheap, large variety of colors, types, etc, tank stays how you set it up, whereas live grows and changes, dont get eaten, no special care
plastic disadvantages: algae grows on em, bases can trap junk under your gravel, dont help nitrates at all, dont reduce algae, fish can tear fins on shapr points,
its really your choice, most people start out with plastic, then switch to live if they want, its up to you