You definitely want to use software for knocking up the plog etc.
The old circular slide rule is just daft.
These days, everything is on the internet: weather, notams, flight plan filing, contacting airports by fax/email, etc. So you need to carry a little laptop, with GPRS/3G connectivity, when travelling, anyway. Or an Ipad if you are a masochist
I haven't done a manual flight plan since the day I got my PPL.
I don't think Skydemon was NATS commissioned originally. I vaguely recall reading they did a deal with NATS quite recently, on some cut-down version.