Every top tier of any company looks for a solid team more then anything else. Having interviewed at YC and talking to alumni everyone talks about the same thing. A solid team with a natural fit that can get through any hard times is essential to build a scalable business. I have also been through techstars.
Working with someone you just met is simply not good enough to get your business funded
Its best to work with someone you know from before. A sort of natural fit. It will help when the business is under pressure or you guys have disagreements.
In hard times you need to rely on a solid team
Every business goes through hard times. Every VC will know this and so will look at the quality of the team and how met before they put any money in. Its common to ask how you guys met and have you done another business before. The team is such a solid part of a business and cannot be underestimated.
Try to work with someone you like but also has different traits to you so you guys can co work. For example someone more tech and another more strategy and fundraising.
We have done a video about why this is important here: