in KL? hardly. In kuching? hardly too. In kampung? hardly also but i am sure some kampung in deep jungle don't have signal. so i respect that u may have that experience. so go for offline in this case. btw, i have sygic in case that situation happens, and for the last 2 years i only used sygic once.

If overseas, Google Maps.
If local, like others, Waze.

Both can still work offline while navigating, but when searching for destination, you need internet.

There's a way to cache Waze's maps for offline using. Not sure how. Just imput something into the search bar.