Contrast top down and bottom up budgeting and state one which  you would employ at an IT Company

Please do some research on top down vs bottom up budgeting. In your post describe the differences between each of these styles of budgeting. Then describe the advantages and disadvantages of each. Then I would like you to state which method you would employ if you were able to choose the method at a company (IT Company) you worked for. Why did you pick the method that you did?