Thomas Owens comment is pretty to the point. Having been been a freelancer doesn't say anything about someone as a person or as a developer.
Personally, I have been working in software development in a couple of distinct capacities:
- As an employee of a (large) consultancy organisation. I would work on their clients' projects at their clients' place of business. An hour-invoice type of deal, this was at a time when the concept of fixed price project was still at its infancy.
- As a freelancer / self-employed contractor. Essentially this was the same as being employed through a consultancy organisation but I had the power to say "no" and could go after projects I liked.
- As an employee of an in-house development shop.
- As an employee of an independent software vendor.
- As a business owner, developing smaller software applications for clients.
What does that say about me as a developer? Nothing.
There are many prejudices about freelancers, for example that they don't have any staying power, are easily bored, can only be trusted with the simplest of assignments. They probably are true for some, because if you do get that itch or your quality isn't up to scratch it may be easier to jump from project to project than to stay with one organisation for a longer period of time.
Freelancers are willing to take their skills and put them on the line. They get the boot quicker than any other employee, often simply because the money ran out or company politics killed the project they were hired to do. If someone has 10+ years experience as a freelancer, he or she has been able to pay the bills for all that time without the comfort of job-security. To me that is a positive. Even spells of many short contracts (3 months) are not necessarily a warning sign, while that would most certainly set alarm bells ringing for someone who was an employee all that time.
And what about someone who was employed all that time by a couple of consultancy organisations? They could easily hide the fact that they were booted from every project they worked on, simply by not mentioning specific/any projects or being vague about their duration.
Or someone who was employed by let's say three big organisations with large in-house development shops? Are they any better? More stable? Again it would be easy for someone with an employment history like that to hide less attractive facts in a general description of their employment. Never mind they were spat out by every team they were assigned to.
The type of contract someone had when working on a project means tiddly squat. Having been a freelancer your entire career doesn't say anything about your worth as a developer. Nor does having been an employed person all your career say anything about your worth as a developer.
Your projects do. Your skills do. Your colleagues do. Your references do.