I like the expression to work like a charm:
If something works like a charm, it is very successful or effective.
Although the expression is general enough that it can be used in a lot of different situations, I probably would not use it to describe how well electronic or mechanical devices work. You can use it to talk about software, however. For example:
That antivirus package that you recommended really fixed my computer. It gothelped me get rid of all the malware orand adware that I had on my PCit. The thing worksreally worked like a charm.