I am having plumbing work undertaken in my bathroom. The plumber has "boxed in" the connections to the basin taps, and I'm going to tile over it - hence (due to the difficulty of removing the tiles and getting access to the connections) I'd like to make sure that the connections are as safe as possible.

The plumber has used compression joints, and tells me that this is just as reliable as soldering. Is this true? Also - if the connectors to the basin taps are flexible, would he be able to use a solder joint anyway, or would he have to use compression joints?