So, base your decision only two factors:
1. Budget (perform a thorough cost estimate before making any changes)
2. Quality of service expectations
The risk part of this is that your company has never had a software team before. This means you have nothing to build upon. The level of risk here is tempered by the flexibility within your available budget, which means how much cost are you willing to absorb outside of plan if this goes to shit.
Now, set your expectations right. Software teams never ever make money. They only cost money. Will moving dev in house cost less money than the current solution? No, at least not at first, but you have to build from nothing. Moving dev in house will allow future scale the outside party does not provide.
Secondly, absolutely forget technology. Don't fucking go there and if you do you have already failed. Think only in terms of leadership. What that means for this effort:
1. Hire a leader who can perform risk analysis, measure things, work within a budget, is super assertive, and communicates brilliantly both in person and in writing. The assertive part is important because opinionated technicians/developers will attempt to drive the plan. Don't ever let that happen. A real leader will own this in both failure and reward.
2. Set realistic goals and accomplish those goals. Don't do anything else. Once the first goals are achieved you will have the foundation to do other things. Every distraction wastes more of your budget.
3. Form, in writing, policies that you are willing to fire people for violating. These should enshrine conduct, ethics, and appropriate standards for quality of service.
4. Do not (ABSOLUTELY NOT) think about this in terms of a startup. You are an established company already generating revenue/profit with margins. Proceed with a well planned vision always accounting for risks and make adjustments to the plan very carefully. Distractions and deviations will cost more money.
5. Finally, transition from the current solution to the in house software team carefully and progressively. This will cost more upfront, but dramatically less in the near term due to lower risk.
Good luck.