Infrastructure as a Service (IaaS) clouds are considered interesting sources of computing and storage resources for scientific applications. However, given the large number of cloud vendors and their diverse offerings, it is not trivial for research projects to select an appropriate service provider. In this paper, we present the results of evaluation of public cloud providers, taking into account the requirements of the biomedical applications within the VPH-Share project. We performed a broad analysis of nearly 50 cloud providers and analyzed the performance and cost of 26 virtual machine instance types offered by the top three providers who meet our criteria: Amazon EC2, Rack Space and Soft Layer. We hope our results will be helpful for other research projects that are considering clouds as a potential source of computing and storage resources.