investing as well as being a bounty participant has its own advantages and disadvantages, investment is the fastest way to get shares from a project but has the risk of losing prices that are even chilling or losing or losing all investments due to scam projects, and being a bounty participant needs a little hard work to promote the project without worrying about losing money, but having the risk of late distribution or not getting anything from a scam project
and if you have to choose between the two, I think investment is a great way to get good profits, as long as having capital and projects is not a scam and getting a profitable market price, then investment is considered successful
If you asking on the side of the user than it depends on your skill levels and funds. Now if you are a person with a lot of money and no skills than investing is obviously the better choice for you, however if you are a person who has insane marketing skills but not have the money to invest than marketing it is a smarter choice. It all comes down to how you can make the most money from the project after all so even if you have marketing skills you can invest if you believe on the project or even if you have funds you can still promote it and get the most out of it but the long term profits will be higher with whatever you are good at doing.
If you are asking from the project managers perspective (which I doubt you are) than the best bet is to get that best skill out of people, finding that funded guy and get him to invest into you or if you find that insane marketing guy giving him all you can so he can have the room to just do whatever he can with his skills to get more people hyped about your project.