Reactivities: interhalogen compounds versus halogens
Here is the answer for which bond (ionic or covalent) is stronger.
There is no direct answer to this question as it depends on atoms that take part in bond formation.For example you might be knowing that a Fluorine- Fluorine bond is weaker than a chlorine-chlorine bond due to high inter electronic repulsion.In another example iodine-iodine bond is weaker than chlorine-chlorine bond.Similarly there is certainly this sort of variation in ionic bond as well.
So if you compare the weakest ionic bond and strongest covalent bond then covalent bond would be stronger.And if you compare stongest ionic bond and weakest covalent bond, then of course ionic bond would be stronger.Also in many substances its not only the bond strength that matters but also the crystal structure.
An example where covalent bond is stronger:Carbon-Carbon bond is stronger than NaCl bond.
Whereas NaCl ionic bond is more stronger than Br-Br covalent bond. 

So it depends on the atoms that participate in bond formation.

visit https://labs.chem.ucsb.edu/zakarian/armen/11---bonddissociationenergy.pdf for bond enthalpy.