How do you choose between product functionality and ergonomics?

In this period of confinement, I decided to upgrade some of the business management tools at my disposal, and naturally I approached specialized off-the-shelf software publishers.

As a well-informed "buyer", I research software that seems relevant to my company's size, desired functionality and look and feel.

The software publishers all offer a well-honed sales methodology, with online appointments and a demo tool that allows us to project ourselves with our own data.

Introductions are made, and I'm accompanied by an account manager each time, who explains to me through a use case the pluses of their software and their teams of developers who are constantly sprinting with a backlog as long as "containment".

They each give me a trial version to try out. It's a very good strategy for making the tool already indispensable.

Basically, the two software products I've chosen deliver the same promise. The first has been on the market for several years, with dedicated teams who have had the time to identify needs and iterate their solution.

The second is a young start-up, starting out with an initial MVP + but with big ambitions to create a disruptive product.

So I made my comparison, and quickly drew my conclusions.

The start-up pushes the user experience to the limit, it's very fluid, rather well thought out and the UI is in line with current trends, especially when handling financial data, which is not the easiest thing to do. The experience is therefore very good but very short, and the software doesn't meet 100% of my needs due to a lack of functionality.

The other editor, who has more experience, offers a wider range of functionalities that fully meet my needs at the moment, but... the ergonomics and design are not perfected and lead to a certain frustration in using the software.

Of course, I have to admit that I'm very demanding on this aspect, and that other users may see fewer obstacles.

So I come to my problem and raise it,

Should we prefer a very good experience but limited response to your needs, or a complete and focused offer with a degraded experience? What would you do, and what would be your decision criteria?