A FMA is considered a good thing to have for a startup. Being the first, you can capture as much of the market as possible without having to face serious competition. A lot of companies in India like Flipkart (ecommerce store), Paytm (online mobile recharge), Grofers (hyperlocal grocery store) etc. have used this advantage to gather good market shares in their respective fields.
On the flip side, having a FMA also has many challenges associated to it.
Educating Customers: Since the product/model is new, customer usage needs to be encouraged through customer awareness and education.
Luring Investors: The first players have the biggest problems in generating investors interest. How big is the market? Is it growing? How much can you penetrate it? These are some of the questions a startup having a FMA will need to address in great detail.
Wastages in Learning: Since you will be the first one attempting to create and market a FMA model, wastage of resources like money and effort are bound to happen.
Team Building: Getting good people for your startup becomes difficult as potential hires are vary of the success of the model and how scalable it is.
Nevertheless, a lot of the biggest companies are the ones who have created and utilized a FMA to their benefit.