To answer the OP:

Likely most have joined Hilton over another chain because it was what the company used or was convenient to where they were going when travelling or a friend/colleague recommended that chain.

I am sure there are as many answers as posters on here though due to the very different situations we all find ourselves in (that brings us to a hotel).

It is worthwhile questioning the reasons for something once in a while instead of just going with the assumed status quo, in case something has changed and the reasons are different from the past, although it is best to put that into the question to show that you realise this has been asked before but is anything different now...

As mentioned, there have been threads on this in the past and likely they are still valid, however, one never knows, especially as there have been several big changes in the various hotel programs over the last year or two.

Personally, what would interest me would be to find out why the Chinese are flocking to Hilton in such big numbers recently? This is obviously a big market potential for any chain and we do see quite a few new hotels going up there but with all the competition, it would be interesting to know what makes people join one brand (Hilton) over the other well known brands in China? (if that is not stealing the OP's thread...)

Hope the OP gets some answers that either confirm the decision factors haven't changed, OR that some new insight comes up.