Real plants are certainly far better. They help use up unwanted elements in the tank, and help to contribute to wanted elements. They look much, much better (when healthy) and I have found that it creates a more natural setting for the fish.
I've done some experimenting and have found without a doubt that fry grow considerably faster in well planted tanks then not.
There are some things to consider before you get them though. Lighting and substrate must be considered, as well as what kind of plants you will be keeping. You also need to decide if you are going to go with c02 injection. Planted tanks are all about balance, and it takes practice to get it right. Not enough nutrients and the plants won't do well. Too much and you will get algae problems. Too much light and not enough co2 will also effect the plants, as well as two little light and too much co2. Then you need to consider that planted tanks are a little more work. Fast growing plans need to be pruned regularly. Leaves will fall off or get torn off, and these should be cleaned up regularly to keep the water cleaner. Algae is something you are pretty much guaranteed to have to deal with as you work on getting that balance right in your tank.
I highly recommend planted aquaria, but I also recommend considering the pro's and con's before jumping in. Planted aquaria can be a whole hobby on its own.