For US customers, PLS8-US seems to be the safest choice for 4G coverage in the US, as long as you don't mind EDGE speeds when roaming outside North America and maxing out at UMTS speeds where you don't have 4G coverage in the US.

PHS8-P / PHS8-J / PHS8-K seem to be the best compromise for global travelers, as long as you don't mind lack of 4G

PHS8-E and PHS8-US seem to be less flexible than the other PHS8 variants, so I wonder what the advantages are with using these modules.