I have been using iYogi for tune-ups on a computer between quarterly and monthly depending on the need. Their tune-ups have resolved problems that I had.
The issue I have with iYogi is that most times when I have gotten a tune-up the iYogi technician has tried to sell me another product, in a quite persistent manner, which I have to say "no" to multiple times before he finally gives up. The most recent time was actually amusing: In mid July 2015 he tried so sell me on upgrading my System 7 to System 8; this was after it was widely known that Microsoft was about to offer System 10 for free. It has also been widely known for several years that System 8 is a dud. I pointed all this out to him but still had to say no many times before he gave up.