I would prefer the data you get from a soil sample but it certainly can be a useful tool. Honestly you can get fairly close pH in your area ,on areas that havent been amended anyway, using web soil survey. It will most often put you within .5 or better on non amended soils.
Pretty accurate but remember...using a meter won't tell you for instance, how much lime per acre you need to add to correct your pH. If you're serious about plots...do it right.