There are pros and cons to both flight and clipping. If the bird is not aggressive (i.e. doesn't fly to people to bite), will not hurt itself (flying into things even after being introduced to the house) and you can provide a safe environment, then by all means, allow him flight!
Flight is instinctual. Not flying into things, turning, banking, landing, etc is all learned behaviors.
Here's one article that tries to point out the pros and cons of each
Should you clip your parrot
If you try to start working on taming him from inside the cage using his favorite treats and allowing him to meet you half way, then it would be easier to allow him flight.
However, if you start training him outside of his cage where he has the chance to get away from you because he's afraid of you, then it's easier to clip him... however, you are then forcing him to be with you rather than giving him the choice to.
[ame=http://www.youtube.com/watch?v=fUx81WHTUwk]1 Bird in hand Leads to Many - YouTube[/ame]
[ame=http://www.youtube.com/watch?v=AlSm4uFZzVU]More Budgies!!!! - YouTube[/ame]
[ame=http://www.youtube.com/watch?v=R9w9w8nMRmw]Hesitant Faye - YouTube[/ame]
[ame=http://www.youtube.com/watch?v=rH9ZWxhCSAE]Not So Hesitant Faye - YouTube[/ame]