REAPER is indeed great, but it’s kind of complicated (not quite on par with Blender complicated, but still). I’ll go ahead and second REAPER, but I’ll also recommend looking into:
MuLab, available free with limitations or a couple of reasonably affordable package options. It’s nice and straight-forward, easy to get started in, but still powerful if you need it.
Kristal Audio Engine, available free for non-commercial use or 25 EUR for single-user license. It’s basically just a multirack recorder/editor, and its main drawback is no apparent support for third-party plugins (VSTs, AUs, etc.).
LMMS, or Linux MultiMedia Studio, a FOS FL Studio act-alike that started out on Linux and has since been ported to Windows. They’ve updated several time since I last played with it, but at least they’re up to version 1
I’ve tried out all of these at one time or another, although some of them have been updated quite a bit since I last fired them up. Of these I’d recommend MuLab or REAPER the most, but I believe MuLab has a gentler learning curve than REAPER, albeit possibly at the cost of power. REAPER is cheaper at its lowest purchase option, but more expensive for a full commercial license.
I likewise would have recommended Garageband, since it seems to be a great program for all the basics and enough of a taste of the more advanced stuff to whet the appetite of neophyte power-users
I don’t know of a good Windows equivalent, though.
And you may be right about prior DAW experience getting in the way. I’d used SONAR and Live before trying out REAPER, so it might be a matter of how things work in one versus the other and wrestling with the difference.