CADer, yes usgs topo maps are decades old, but mountain tops and ponds and streams don't "move" so for me they work fine. Besides i never go out into the backcountry anyway without printed topo maps, whether they are from the usgs or published trail maps. Besides the usgs maps also show locations of other features such as shelters, mines, swamps & wetlands, etc. which is incredibly useful out in the wild. in my experience they are still relatively accurate despite the age of the maps as you pointed out. Its just a matter of personal preference and i'll stick with usgs topo maps that have been vetted over the decades.
Now onto GPS Kit......don't get me started. The app is a waste of money. I purchased it not to long after it came out and after using it a few times i removed it from my phone. It would constantly crash on me, the dashboard that i customized would constantly switch back to default settings. in fact i even wrote the developer about the problem and he said he would fix it and then waited for the next release, and it was't fixed in the next release so i gave up. Also, i found the timer thing that always ran in the background retarded to say the least. It made no sense to me. it served no real purpose. however it seems as if the app has had a major release and some nice new features, though i probably won't ever use it again.
in any case you should check out motionx gps, a much better designed app that i bought to replace gps kit. it really kicks gps kit's butt and motionx gps also has topo maps that you can cache for offline viewing. Though, motionx gps doesn't use google topo maps which is a source of angst for me. In any case, i don't ever use it in the backcountry. as mentioned in a previous post, if i'm hiking or climbing, i'm usually at it for 5-8 hours and the iphone simply doesn't have enough juice. not to mention i don't want to keep my iphone in a location that will ensure a good gps signal. that's what my suunto gps watch is for.
i'm simply looking for an app utilizing usgs topo maps, that will display my position within the usgs topo map and allow me to set waypoints. that's it. plain and simple.