Can't decide which research project to work on as an undergraduate to prepare for graduate school? I'm an undergraduate engineering student at a top state university. I want to do high-quality research to build up my experience in preparation for graduate school (MS/Ph.D.). My research is out of pure interest, not volunteering or doing it for credit hours.

My goal is to go to a top 5 graduate school in my field. I have some experience in research since I worked on a research project last summer. I published a paper as a second author on that to a conference and it was accepted.

I found two research projects currently and they're equally as good but I'm having trouble deciding which one would help me the most due to my lack of experience. It would be super helpful if those of you who have been through this process can provide some advice.

Project 1


Professor went to a top 5 graduate engineering school.

He is currently in my engineering school but not in the same
department as I am.

Open-ended project. The project hasn't been worked on much in recent
years so I have full choice over the direction of the project.

Collaborate with one graduate researcher on this project.

Prof. said I have a chance to publish papers since it's open-ended
and I end up discovering something novel.

The project is directly related to my field and future research I
want to pursue.

Professor: h-index: 23, Citations: 2123


Project 2


The project is an application of my field, but the work is still
related to future research I want to pursue.

The professor is in the College of Science which is a difference
since I'm in engineering and he does not have specific knowledge
about my field.

I'm assuming this means not many connections in my field.

The project is interesting, a novel application of the research in my
field.

Work with 7 other undergraduate researchers from different majors,
and two graduate researchers.

It recently received a huge check from NSF.

Professor: h-index: 21, Citations: 1299
I am by no means an expert in the realms of academia, prestige, or research papers and am an M.S. student myself, but my logical evaluation of this situation is that you probably have more to gain by doing project 1, for the following reasons:  

1) Professor 1 is probably a better connection to have in the long run, especially if the school they went to is one of your top two picks. He/she will probably be able to be more helpful with explanations and sticking points during your research than Professor 2 as well, if only because they share a more similar background to you and can understand your mindset better.

2) Project 1 seems (from your description) as though it is more likely to get your name on a published paper, which is always a perk when you put months of work into something. 

3) Project 1 has fewer people involved. More collaborators is not necessarily a bad thing, but it does allow for more time lost to communication (or miscommunication), introduces more potential for error, and almost certainly requires some overhead in the form of proper project management in order to efficiently utilize everyone. A two person project, while it can certainly benefit from the same processes, would not need nearly the same amount of organizational structure. Another thing to mention here is that having a majority of undergrad researchers on the project may mean that it goes slower than you might like, due to the fact that they are less experienced than you

Keep in mind, though that bigger groups introduce more perspectives and usually better ideas. Additionally, the undergrads at your school could be brilliant and leave you behind, rather than the other way around  

4) Project 1 is more directly aligned with your interests and should serve you well going forward. Especially since you have essentially been offered complete control of Project 1, you can shape it so that it directly feeds into the next project you want to take on after you complete this one.

5) Finally, I would like to recognize both of the original commenters for their contributions, because they are absolutely right (Sorry for omitting tags, fairly new to SE):
    - a) If the project is not interesting to you, don't do it! I only wrote this as a guide with the assumption that you were equally interested in both, because you said both were "equally as good"
    - b) Evaluate the professors based on their own merit and what you know about them personally. If you don't know them well, try to find students that have had their classes and ask them. Try to get a feel for their personality and ask yourself if you're comfortable working with them for a long(-ish) span of time.