I like everest home, it is the best tool of its kind IMO. It's just that the information it reads may be innacurrate. But it would appear like your 12V is low, I'd just understand that it is usually low from overload. Adjust away if you can keep the 5V reasonable at the same time, I'm just fairly certain a new power supply powerful enough not to droop will help a lot more.
As far as meters go, the real name is Fluke. They make the only ones that are for sure good enough to be worth much extra money. It takes about $99 to get a basic Fluke, but it is worth the investment if you intend to work with circuitry as well as basic connection concerns. If knowing you are spending smart money means as much to you as the absolute economy of the solution, a Fluke is the only way to fly. They have many models with differing types of advanced and specialized functions as well as rock-solid measurment capabilities, including data logging and other types or measurment beyond the basic DMM functions (such as temperature or frequency) for more money.
http://stores.yahoo.com/tmt/ser7eltes.html
Beyond Fluke, if the meter is built well and solid it will probably contain circuitry very much like any other at that general price/feature set. I have a Blue Point (a SnapOn company) that is OK, but it's certainly not Fluke quality and probably originally cost about as much.