We chartered with Horizon recently and used their cell phone to call them a couple of times, and otherwise relied on my T-mobile phone with an international plan, with a caveat. T-mobile is usually worse than ATT but not sure if there is a difference there because we're probably all roaming off the same network. My phone acted as hotspot for wife and kids and it was slow but ok for casual browsing. The one time that I really I wanted a fast connection, for the playing the BoatyBall challenge when we were going to Anegada, I got up early enough to dingy in to Bitter End to use their wifi. Renport was just too expensive to justify. I'd say for just 10 minutes of work here or there, I'd go with the cell phone if you're not on zoom or something like that where good connectivity is vital. Your remote desktop/VPN settings can make a difference too - set them for a slow connection.