When it comes to finding the best job/project tracking add-on to Xero for a commercial construction contractor, it's important to consider the specific needs of the construction industry. Here are some key points to keep in mind:

1. Integration with Xero Accounting: Look for a job/project tracking add-on that seamlessly integrates with Xero Accounting. This will ensure that your financial data is accurate and up-to-date across both platforms.

2. Job Costing and Budgeting: Choose an add-on that allows you to track job costs and compare them to your original budget. This is crucial for monitoring the financial health of your construction projects.

3. Time Tracking and Attendance: Consider an add-on that offers time tracking features for your employees. This will help you accurately track labor costs and ensure that your projects stay on schedule.

4. Inventory Management: For construction companies that deal with materials and supplies, an add-on with inventory management capabilities can be highly beneficial. This will help you track stock levels and manage reordering efficiently.

5. Project Management Tools: Look for an add-on that offers project management tools such as Gantt charts, task lists, and milestones. This can help you stay organized and ensure that projects are completed on time and within budget.

In conclusion, when searching for the best job/project tracking add-on to Xero for construction company, make sure to prioritize integration with Xero Accounting, job costing and budgeting features, time tracking and attendance capabilities, inventory management, and project management tools.