of course a good investor will first do its own research (whitepaper, roadmap and etc), besides that what is your biggest motivation?
The main thing that usually gets my attention is when there are big names attached . If I see that an investment is attached to a big name I will usually feel kinda confident about it, cause since they are operating with a big brand why wont it be a good one? So its probably going to work out, but that doesnt stop me from making the proper research that Im supposed to make though. I still need to check everything about it to know if its going to be truly a good one.
You need to be careful with that approach because as far as I know it is not weird for projects to pay people that are known in the field of cryptocurrencies, it is just a marketing move they may seem involved in the project but the truth is they are not, the only involvement they had was to get paid by the project and you cannot rely on the opinion of someone that is being paid to give a positive opinion.