I choose a hotel more about of the location and the rate than the brand.

The HIX are new and most of the time in better conditions, as they have a standardised room. The HI are franchised and more or less differ in the room and the interior equipment as they are often converted hotels which joined HI later. This will be one point, if I book a to me yet unknown hotel.

But, if I have to choose between a HI and a HIX I will opt for the HIX.