I'll say it again, Windows RT is not an "also ran". It's a perfectly viable competitor to Android and iPad. Performance is perfectly acceptable. An off-the-shelf ARM SOC is not going to perform as well as an Apple-tuned SOC in the iPad. Android has had years to tweak performance.
My wife has had zero complaints. I know this is only one person, but it's someone who knows what she wants and doesn't hesitate to send issues to her "sys admin".