I've talked to some people that have quality tested several different brands, and the results were that Autometer gauges are no less accurate than the more expensive gauges such as Apexi, Blitz, HKS, Greddy, Defi, to name a few.
You also need to decide if you want mechanical or electronic.
Mechanical gauges require you to provide a source of what is being metered to the gauge - ie for boost, you will need to run vacuum line to the gauge.
Electronic gauges usually have a metering device that can be mounted in the engine bay, which in turn connects to the gauge with a few wires. This is good for metering things like oil or fuel - you don't want to lines for those in your cockpit
Also, electronic gauges allow you to set warnings, hold peak, and memory. These will most likely require a separate controller unit.
Do some investigation and pick the one that best fits your budget and needs. The more expensive gauges look nicer at times, but also, sometimes that is what you are paying for - vanity. If you just want functionality, Autometer should do the trick.
