I always use a PLOG for all but a local flight in very well known territory (and even then, probably have the PLOG sheet on my kneeboard to write down useful numbers).
I've used the SD PLOG a few times. It works, but I find it a bit sub-optimal.
Here's the trick I worked out a lot of years ago. I have a computer, it has a word processor on it. Design your own, to suit the way you like to write stuff down. Make sure it's compatible with SD, or any other software package you use - but if you designed it, it'll be right.
Printing out half a dozen to keep in your flight bag is easy, copying the critical numbers from your software is also easy. Drawing a line on a chart's not a bad idea either.
Yes the SD plog works, yes it's not a bad idea having stuff on paper in addition to anything electronic. No, it won't work as well as a PLOG you designed that suits your style of flying.
My PLOG is at probably its 10th revision in 15 years since I realised I could do it that way, and each one gets that tiny bit closer to personal perfection.
As for winds, they're never what the Met Office forecast, and your interpolation is always a best guess. Also, few aeroplanes fly quite at the speed in the POH (came across one the other day that actually went faster!). So, don't get too hung up on how exactly you use the numbers off the forecast, as they'll be a bit out anyhow.
GPS is great - use it. But integrate it with old fashioned methods: don't use it to replace them.
G