Went to Jamaica, Cayman and Cozumel last week and only encountered two issues with the Telnamobile SIM. The first was my issue as I didn't have the APN set right when we were in Jamaica, so no data (darn .com vs. .net). The second was my phone would not register on ANY network in Cayman. Phone even listed all the networks that it found as "forbidden"... Hmmmm.... Worked like a charm in Cozumel, where Telna made some revenue off of us. First time we had data all week
No idea what the speeds were, all I know is that it worked for what I needed...