The least expensive analyzers have a standard 2 valve manifold and no vacuum gauge while the more expensive models typically have a better 4-valve manifold and a vacuum gauge. At least two models feature wireless data connectivity as well. Be aware that the prices you see usually do not include hoses. A good set of hoses can cost $100 if you are getting three 1/4” charging hoses and one 3/8” vacuum hose. If you are getting large hoses, such as Appion 3/8” or 1/2” hoses, they can cost $100 a hose. So when shopping, make sure you are getting an analyzer, a manifold, and hoses - unless of course you are going to use one or more of those pieces you already own.
The gauges that read vacuum typically switch from displaying pressure to displaying microns of vacuum at some point during the evacuation. On the subject of vacuum, one problem with having a vacuum gauge built into the gauges is that the gauges are not the best place to be checking the system vacuum. However, I have used a Fieldpiece set like this and have been generally pleased with the result. So far, our Fieldpiece SMAN4 set has held up well under student use. Yellow Jacket has a built in vacuum gauge in theirs, but a separate vacuum sensor so you can still measure the vacuum at the unit but use the built in vacuum gauge in the analyzer.
Hilmor has a digital gauge set that has both analog like displays and a digital readout. It looks a bit more like a traditional gauge set but still gives you all the digital goodies. I find the Hilmor gauges the easiest to use – no screens to scroll through and all the information on display all the time. Imperial has a brand new i-manifold which has no display! It uses Bluetooth to connect with your smart phone or tablet and uses that as the display. With the display being part of an app, it can do a lot more things and be more easily updated. You can download the app for free and use it by entering the temperatures and pressures. Pretty shrewd move! Once you get hooked on the app you will want the manifold to go with it, like the story “If You Give a Mouse a Cookie.” If you are not conversant with that reference to classic literature, you probably don’t have kids. Finally, my friends at Appion are coming out with digital high side, compound, and vacuum gauges that connect to the side port of the valve core tool they sell. No manifold needed!
I have uploaded a table of available digital system analyzers with a summary of the features of each. The file, “Digital_Gauges,” is in the Survival Kit on my Google Drive. I gleaned these from information available on the internet. The Appion gauges are not included because they are not released yet, but I saw them in March at the instructor’s conference in Baltimore. The address for the survival kit is https://drive.google.com/#folders/0B0i1Mw3czgHrLTN4M1p1LVh6Yms