Hi,
You rbest bet is to read the comments on each asset store reviews, they are very true to how well they work and everything.
Not yet tested any of them, do I can't really tell more on them.
U3DXT seems to be the most direct way since it's only giving access to the native API, so it can't go wrong or assum certain way of doing things. The downside is that you'll have to properly learn xcode api... and that may very well put you off big time...
bye,
Jean