Kind of a loaded question...
What are you driving?
How high an air pressure do you need to check?
What's the access to your tire valves?
I always used pencil gauges. The few mechanical ones I'd tried were cheap and fell apart.
Got our first Class C. It had no wheel covers and had useful hand holes. Bought a Victor brand pencil-style gauge with Angled Foot for truck tires.
The C we have now, had RUBBER valves in Ford wheels with the tiny round hand holes. HAD to use a long trucker-style gauge with Straight Foot. AND a similar Air Chuck.
Now we have Borg Dually Valves with Air-Through Caps. That old Victor works great, and I've actually found the free pencil gauges from Discount Tire are accurate. I have an inflator with gauge from HF and it's accurate too. Used it enough to start wearing its hose out.
A steaming high air pressure isn't an issue since the first C was limited to 65PSI and the one we have now, 80PSI.
So, what do you need it for? I noticed one of the nice gauges linked here only went to 60PSI...
Those of you With Dual Tires and Without Custom Valves might like
this one from Amazon: