Hello Ellie,
I personally like the idea of intros as they provide excellent brand recognition, but maybe I am slightly biased because making them is a large part of my business, haha.
If you are worried about losing the engagement and attention with your audience in the first few seconds of your video because of using an intro, I might suggest emulating what Tim Schmoyer does with his YouTube channel, Video Creators. If you are not familiar with his work, basically what he does to immediately engage the viewer in the first few seconds of every video is by saying something very breif and insightful to summarize the video, and then he rolls the intro. Keep in mind you will need to keep it concise and engaging if you choose this method to begin your videos, but it can be a very effective way to get people to stay for the rest of the video. Also remember that this method requires a certain personality for it to feel natural, and some YouTubers should honestly just either roll their intro if they have one.
Well I hope this helped you in making a decision. Good luck with your channel![DOUBLEPOST=1422746824,1422746191][/DOUBLEPOST]To add on to my previous comment, an excellent way for gamers to engage their audience in the first few seconds of the video before rolling the bumper is by playing a particularly funny or epic part of the upcoming video to catpivate the viewer and entice them to continue watching to see more content like it. I see this being done by increasingly more gamers---JackFrags to name one does this occassionally.