I've got one of these.
https://www.google.co.uk/search?q=giant ... QxWoN2KMtM:
It seems accurate enough, and I've cross checked it against other gauges known to be accurate.
The "Giant" branded model doesn't seem to be available now, but there are very similar gauges by,for example, Rolson and other Far Eastern makers. I can't speak for their quality.
I find mine handy to use, rubber-armoured enough to stand kicking around in cycle bags, and of course it handles both valve types. The only downside is that it's quite heavy, if weight is a consideration.
Being analogue and mechanical, it doesn't suffer from a hard-to-read digital display or need a battery.
