It really depends on the quality of the teachers and management at the studio.
In general, people who compete tend to prefer independent studios and independent teachers because the costs are lower (especially for competitions) and the level of instruction is often higher. There are no contracts, although often you can buy "blocks" of lessons.
I first learned to dance at a franchise studio and it was very good experience. The studio was well-managed and they sponsored visas for some talented European dancers to come there and teach. So, even though it was a franchise, we had people teaching there who recently have been in the top two in the US in their style. My teacher later became a US champion. I didn't have a lot of money and couldn't afford the standard competition packages, but we always worked out something that allowed me to compete at a price point I was comfortable with. In many respects I was very fortunate, because I've heard horror stories lately of people being asked to pay as much as $10,000 just to dance in a studio showcase!!
So, basically, shop around at all your options, both franchise or not. Check out the teachers and classes. Ask lots of questions. Don't sign anything anywhere until you feel like you understand your costs, what you're actually getting, how accomplished your teachers are, how good a job they've done with their other students, and what their group classes and practice policies are like.