I'm not that fussed one way or the other, I've got used to Azuma First Class now and, as a few have commented above, rickety mk4 seats are becoming as big a problem again now as they were before the VTEC refurb.
I'm not aware that one train type is any more likely to bring down the wires than any other, but I did have an overhead power problem in an Azuma just north of Alnmouth on Monday of this week. We came to a very abrupt halt, sat for a minute, they explained, the engines fired up and off we went again, and we stayed on diesel to Newcastle. Not too bad I thought...