The basic issue with VFR GPS usage is that the only really clear representation is the "printed" chart, and this is not released by the CAA other than a non-rotatable single layer image, licensed to Memory Map and maybe some others.
All the more common GPS maps are vector-based and come from Jeppesen, and are IMHO pretty crap. They are OK if you are always referring to the real printed chart, but this gives you a lower level of situational awareness than running the real chart as a moving map.
I've been banging on about this issue for several years. Memory Map was the only game in town for a long time, but you needed a windoze tablet computer to run it in flight, which is OK but not good for techno-challenged pilots.
Only recently have a few GPSs appeared which do basically that but in a self contained "aviation" product. They look very good, but one needs a 7" or bigger screen, for reasons stated.
However
AFAIK none of these units offer anything for outside the UK. Out there, the only VFR charts which are available in electronic form are the Jepp "VFR/GPS" ones and the licensing terms on those are really steep.