We don’t implement tail calls in the new VM and don’t have special optimizations for recursive functions - function call cost is lower in the new VM but that’s just an across the board improvement. A recursive factorial runs ~1.5-2x faster in the new VM compared to old VM I believe.
A non-recursive algorithm is generally going to be faster in our VM unless you need to go out of your way to maintain some sort of custom stack. A non-recursive factorial runs ~2.5x faster than recursive factorial.