Optical Burst-Switching (OBS) has been envisioned as a cost-effective paradigm for supporting Internet Protocol (IP) packet traffic over optical transport networks. OBS network performance is hampered by resource contention at the network core nodes, requiring efficient strategies for minimizing and/or resolving contention. Although the use of deflection routing to resolve contention in the space domain has been extensively studied, the use of proactive multi-path routing to minimize contention in advance has been almost neglected. This paper assesses the performance of OBS networks using either reactive or proactive multi-path routing and reports on the merits and shortcomings of both approaches.