Yes Chris I recommend windows term services over HTML5 as you can control the display, etc much more easily through terminal services settings.
Note: I haven't done a bandwidth consumption comparison between the two, maybe you can turn on both options for this end-user and ask them to use the one that seems better.
Let us know if you end up doing a comparison or if the end-user compares both and prefers one of them more than the other.
For me the edge that html5 offers is that it will work from any client OS, if this is not a constraint I would still prefer terminal services.