I personally would not count on suite upgrades so would not base my hotel choices on this. It's a nice bonus when it happens but you should always be prepared to stay in the room you booked. Perhaps the inverse makes sense...finding out which hotels are near impossible to get and avoiding those.

By virtue of obtaining globalist status you will receive 5 SUAs (if you choose it at 40-nights) which I'd definitely maximize to book into a suite for up to 7 nights.