If you like Imogen Heap, I do suggest actually purchasing her music. Like someone mentioned above, she's handling a lot of the work herself, which means she's probably actually making decent profits off of CD sales, unlike most artists.
Electronic is one of the better categories to label her under, but it's not totally accurate. She's a bit difficult to pin down, which of course is a good thing
Personally, I label her as "good."
Glad to see others are enjoying her music as well; I stumbled upon her out of total accident.