An in-house team gives you the deepest product knowledge. The developers internalise the business domain in a way no external team will match, and that knowledge stays in the building. The catch comes in the form of slow hiring and fixed overhead: filling a senior role routinely takes several months, getting someone productive adds several more weeks, and the payroll keeps running through the quiet quarters.
Full outsourcing means the vendor owns delivery: the provider staffs the project, they manage the plan, and angularjs vs vue they carry the risk of missing the date. This fits well when the work is a defined project and you have a decision maker with time for it. It works badly when nobody on your side owns the product, because the provider cannot guess what the business wants.
Staff augmentation sits difference between laravel and django the two: you add engineers and keep responsibility for delivery on your side. The main advantage is speed — a matching profile is often available almost immediately — and it winds down as quickly as it ramped up. The trade-off remains that your own leads have to have time for code review and planning. Without strong internal leadership, you end up paying for effort with no owner.
Most of the time, companies blend them. One durable pattern puts the architecture and the core domain inside the company, while an outside vendor handles peaks, well-defined modules or platform work. The line is easy to state: retain what differentiates you, and outsource the well-trodden work.
A few questions resolve most of these debates. First: is what you are building the product itself, or internal plumbing? Then: how long will the work last — months or years? Third: who owns it once the vendor leaves? Work through them with real answers and the right arrangement becomes obvious.