For creating new coin you must be serious about the project, don't just create for the sake of raising money, but you should be determined to deliver a useful product to the public, for this you have to build a team from scratch need a lot of work & time to begin. You would also be needing some initial capital to pay for the team expenses etc.
On the other hand investing in an ICO is easy, you only need money & it is not time-consuming you just have to keep yourself updated about the coin so you can take right moves when to sell & when to buy again, apart from it initially you have to spend a lot of time to do research about ICO project you are going to invest.