Today, many smart phones and tablets have multiple interfaces (i.e. WLAN and 3G). These multiple interfaces can be utilized simultaneously by a multi-path transport protocol to provide bandwidth aggregation or reliability. However, in order to design efficient multi-path scheduling and congestion control strategies, it is crucial to understand the behaviour and properties of the underlying paths first. WLAN links have already been studied extensively in the literature. Therefore, in this paper, we focus on Mobile Broadband (MBB) networks that are in use today. We utilized noun{NorNet Edge} nodes that are connected to up to five different 3G ISPs (UMTS and CDMA2000), hence, providing a realistic view on the QoS characteristics that are experienced by end-users of these MBB networks. We present QoS characteristics (e.g. bandwidth, delay and loss) and discuss our observations. Our results shed light on what a multi-path transport endpoint has to expect - and to efficiently cope with - when using today's MBB networks as transport paths.