I have been using a Garmin E Trex standalone GPS for many years.
It is purpose built for GPS only and is extermely reliable and
accurate.
Go to Google Earth, put the cursor on a spot in Singapore, read off
the coordinates & key it into your GPS unit and bingo, when you
are physically at the actual spot with your GPS unit, you are dead
on target plus minus 30 m max using the coordinates keyed in.
Despite the adverts, overhead foilage can disrupt the weak GPS
signals.
If you are a serious geocacher, stick to a GPS from Garmin or
Magellan. They are cheap and cost about S$200 to 300 for a basic
model.
The US Govt spent more than US$ 20 billion to put up the system and
you only spend S$ 200 to know your exact position anywhere in the
world. This is a real bargain !