Well, I've been using v3.975 for a couple of days now, here's what I've seen.
** I first tried it on an Aspire One 150 netbook (2gb ram. 500gb HD).
MyTopo & OpenStreet are nice, OpenCycle is really nice!! But, after about 5 minutes in OpenCycle TF would freeze up (task manager says "not responding"). OpenStreet would last a little longer (maybe 10 to 15 minutes) before freezing-up. Color, landsat, B/W, Topo, Canadian, Land Ownership, TopoWMS map worked fine as in previous versions. I have not had any problems with this netbook & TF it had worked GREAT; I use it with a Garmin Vista out in the desert.
** I thought it must be a problem with the netbook,so I tried it on the desktop (Dell 9100). Still freezes up in OpenStreet & OpenCycle (did I say that OpenCycle is really nice??), sometime it takes a little longer, but it will freeze up TopoFusion. As in the netbook, if I don't use the new maps TF works fine (as before).
** OpenStreet & OpenCycle bring in alot of wrong tiles. The Map Tool does not work with these maps, so I can't reload those wrong tiles.
_Charlie
BTW, did I say that OpenCycle is really nice??