The Omega was designed to be very easy to use, versatile, and particularly good on coins. Good machine for a beginner, yet with performance high enough to be taken seriously by experienced detectorists.
Another machine you might want to take a look at is the G2 (or the similar Gold Bug GP or Pro), which is also very easy to use, even more versatile, and particularly good at finding coins among iron trash although not quite as "deep" on coins in clean ground.
You asked about electrical interference. As some other people have posted, all metal detectors are vulnerable to electrical interference, but not necessarily to the same kind or degree. The G2/GB machines have a reputation for rarely having much problem with electrical interference. Between the Omega and (for instance) the T2, in a given area one may be affected and the other not, whereas in a different area the situation may be reversed. If you're experiencing electrical interference, there are basically two solutions.
1. Turn the sensitivity control down, that's what it's for.
2. If you leave the sensitivity cranked up, you may notice that when the detector is not in motion there's a lot of chatter, but as soon as you start swinging over the dirt, it calms down a whole bunch. This is a more sensitive way to search but you'll have to put up with some false noise.
--Dave J.