Ask HN: To merge or not to merge (small business)

ASK HN: I'm a fairly successful small business owner working with large media companies helping them with performance and development process work as well as building websites. I have nearshore freelance staff working with me in Eastern Europe for site builds e.t.c. However I am essentially a one man shop. Lately I've been talking to two other small business (one man and a two man) about us merging so we can "get bigger jobs". It seems like we fit well but I can't get rid of one nagging feeling that it isn't quite right. I'm not sure whether it is the control freak in me or some form of risk aversion. We tend to procrastinate over the smallest of things like whether to open a bank account with HSBC or Natwest and whether the geographic location of our accountant matters. All of these things I hardly think matter at all. If a company doesn't hire you based on where your accountant is then you probably didn't want to work with them anyway. The other business owners are known in our shared community. This is how I met them. I even said up front to them that we should work together up front before forming a company on a trial project where we bid as three companies. They weren't too interested in this as they immediately wanted to start building up a business history. I think the chances of earning higher and more frequently are available and we want to build products as well as sell our services. A part of me feels like we are just merging not to solve a problem but instead to make our lives easier, which it would, which is a big consideration. The other guys are very professional and I am sure that when working together it would be fine. Am I just worried? One thing I heard again recently was the advice on hiring. "If there is any doubt then it is a no" Does that apply to business partners? Has anyone done this with good or bad results? Any advice?