Thanks @Martinn for sharing you reviews ,
If you've contacted them multiple times and they've consistently resolved your issues, that's generally a positive sign. They are an independent support company, and there are many similar companies that provide technical and accounting related assistance.
As with any third-party service, it's a good idea to review the terms of service and avoid making large upfront payments unless you're comfortable with the agreement. If you need assistance, you can also contact Quicken directly, or, if you've already purchased a support plan from this company, continue working with them as needed.
Ultimately, the choice is yours. We've seen some users report good experiences with independent support providers like this because they offer a one stop solution for a variety of technical and software-related issues. The best approach is to evaluate the quality of service over time and decide whether it meets your needs.