A year ago I replaced my pfSense box with a MikroTik. People keep asking if I regret it, so here's the honest answer: mostly no, occasionally yes.
The wins are real. The hardware is cheap, sips power, and RouterOS does VLANs, BGP and proper queues without feeling like a science project. Once it's configured it just sits there, cool and quiet, for weeks on end. My pfSense box was a perfectly good general-purpose PC pretending to be a router, and it always felt like overkill in a warm metal case.
The cost is the learning curve, which is steep and occasionally cruel. RouterOS has its own logic, and the day I locked myself out by reordering a firewall rule taught me to always have a scheduled config rollback armed before I touch anything live. pfSense's web UI held your hand more. MikroTik assumes you meant what you typed.
Would I go back? No. But I'd tell anyone considering it to budget a weekend for the docs and keep the old box on a shelf until you're sure. I did, and used it twice in the first month.