Location-based services (LBS) play an increasing role in mobile systems and applications. In this paper we focus on LBS in a multi-provider framework. Using multiple providers reduces dependencies, increases geographic and functional coverage, and allows distribution, load balancing, and fail-over. However, the framework must ensure substitutability of services. We describe the use of a rule engine to dynamically determine a near-optimal provider for each request. The choice is based on performance, reliability, geographic coverage, as well as more intangible considerations. Overall performance, coverage, and distribution can thus be increased at the framework-level.