With increasing mobile usage and more demands for higher-speed data, shortage of spectrum is seen as becoming in a limiting factor in growth of new services and traffic volume. Regulators, such as the FCC and Ofcom, have been considering how to improve availability by spectrum, including by encouraging spectrum sharing between operators. One aspect of any mobile service that needs to be taken into account is how to ensure the appropriate level of service to individual users. This was something considered in our previous work but not in the context of systematic spectrum sharing, nor in the literature on spectrum sharing. This paper addresses that issue by applying QoS consideration for every user in the main spectrum sharing approaches described in the literature, particularly with orthogonal spectrum sharing between operators, both for equalright sharing and non-equal right sharing. The objective is to serve as many as possible users that meet their QoS requirement during the spectrum sharing. Because a flexible spectrum sharing mechanism achieves service-level performance differentiation between operators, it can help operators to set and meet their business plans more precisely and predict the impact of spectrum sharing on the QoS achievement. The results of simulations presented in this paper show the flexibility of this approach.