I fly a Cub (did fly Tiger Moths, Austers etc.). So it's daytime good VFR for me. Following line features (roads esp) seems to work. I keep a note on the 1:250,000 chart as to where I am.
Seems to work and I've clocked up about 500 hours (just think what else I might have done with the money...).
As to a GPS, I now and again use my car one. Managed to buy an aviation program plus charts for it and find that it's a useful aid to let me know where I'm at.
I like being able to set up a route with waypoints and match that against my chart though I'm getting to know SE England well enough to recognise where I am.
In conclusion, use a GPS as a secondary aid in VFR? Yes. Why not?
Roger